@article{cordon_li_yang_neate_unocic_li_moore_sutton_2024, title={Butene-Rich Alkene Formation from 2,3-Butanediol through Dioxolane Intermediates}, volume={12}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.4c01155}, DOI={10.1021/acssuschemeng.4c01155}, abstractNote={The cost-effective production of sustainable aviation fuels (SAF) remains a major challenge within the energy sector. One approach to address this is the fermentation of biomass feedstocks into oxygenates followed by catalytic conversion to alkenes or other oligomerization precursors. 2,3-Butanediol (BDO) is a promising fermentation product due to its four-carbon nature, its decreased microorganism toxicity and associated higher maximum fermentation titers relative to other alcohols and oxygenates, and its capacity to be readily converted into butene isomers and longer chain alkenes. BDO conversion is currently constrained by separation challenges for BDO isolation due to its high boiling point and hydrophilicity. This work expands upon previous BDO reactive separation via dioxolane formation over a solid acid catalyst by investigating the conversion of dioxolanes into alkene mixtures. Dioxolanes were formed from a range of aldehydes and subsequently converted over a Cu/ZSM-5 catalyst (448–523 K) via an ether cleavage, hydrogenation, and dehydration reaction network to form alkene-rich product mixtures (96% C3+ alkene yield, 523 K). This selectivity is greater than that of direct BDO conversion to alkenes over an identical catalyst (89%, 523 K). C3+ alkene selectivity is maximized between 498 and 523 K at complete dioxolane conversion without significant alkene hydrogenation to alkanes. The alkene product distributions can be tailored via both aldehyde selection during dioxolane formation and the dioxolane conversion reaction temperature. Alkene mixtures from dioxolane conversion predominantly reflect the carbon chain length and stereochemistry of BDO and the initial aldehyde at or below 498 K, yet higher reaction temperatures yield alkene mixtures of similar carbon chain distributions, regardless of initial aldehyde selection. Deactivation of the Cu/ZSM-5 catalyst is observed for multiple steps of the overall reaction network but can be minimized by facilitating the complete dioxolane-to-alkene reaction network at temperatures of at least 498 K.}, number={23}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Cordon, Michael J. and Li, Meijun and Yang, Xiaokun and Neate, Peter G. N. and Unocic, Kinga A. and Li, Zhenglong and Moore, Cameron M. and Sutton, Andrew D.}, year={2024}, month={May}, pages={8702–8716} }
 @article{purdy_collinge_zhang_borate_unocic_wu_wegener_kropf_samad_yuk_et al._2024, title={Dynamic Copper Site Redispersion through Atom Trapping in Zeolite Defects}, volume={146}, ISSN={0002-7863 1520-5126}, url={http://dx.doi.org/10.1021/jacs.3c13302}, DOI={10.1021/jacs.3c13302}, abstractNote={Single-site copper-based catalysts have shown remarkable activity and selectivity for a variety of reactions. However, deactivation by sintering in high-temperature reducing environments remains a challenge and often limits their use due to irreversible structural changes to the catalyst. Here, we report zeolite-based copper catalysts in which copper oxide agglomerates formed after reaction can be repeatedly redispersed back to single sites using an oxidative treatment in air at 550 °C. Under different environments, single-site copper in Cu–Zn–Y/deAlBeta undergoes dynamic changes in structure and oxidation state that can be tuned to promote the formation of key active sites while minimizing deactivation through Cu sintering. For example, single-site Cu2+ reduces to Cu1+ after catalyst pretreatment (270 °C, 101 kPa H2) and further to Cu0 nanoparticles under reaction conditions (270–350 °C, 7 kPa EtOH, 94 kPa H2) or accelerated aging (400–450 °C, 101 kPa H2). After regeneration at 550 °C in air, agglomerated CuO was dispersed back to single sites in the presence and absence of Zn and Y, which was verified by imaging, in situ spectroscopy, and catalytic rate measurements. Ab initio molecular dynamics simulations show that solvation of CuO monomers by water facilitates their transport through the zeolite pore, and condensation of the CuO monomer with a fully protonated silanol nest entraps copper and reforms the single-site structure. The capability of silanol nests to trap and stabilize copper single sites under oxidizing conditions could extend the use of single-site copper catalysts to a wider variety of reactions and allows for a simple regeneration strategy for copper single-site catalysts.}, number={12}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Purdy, Stephen C. and Collinge, Gregory and Zhang, Junyan and Borate, Shivangi N. and Unocic, Kinga A. and Wu, Qiyuan and Wegener, Evan C. and Kropf, A. Jeremy and Samad, Nohor River and Yuk, Simuck F. and et al.}, year={2024}, month={Mar}, pages={8280–8297} }
 @article{cagli_klemm_ali_gai_unocic_kidder_gurkan_2024, title={Tuning Surface, Phase, and Magnetization of Superparamagnetic Magnetite by Ionic Liquids: Single-Step Microwave-Assisted Synthesis}, volume={4}, ISSN={1944-8244 1944-8252}, url={http://dx.doi.org/10.1021/acsami.4c02000}, DOI={10.1021/acsami.4c02000}, abstractNote={Achieving colloidal and chemical stability in ferrofluids by surface modification requires multiple steps, including purification, ex situ modification steps, and operation at high temperatures. In this study, a single-step microwave-assisted methodology is developed for iron oxide nanoparticle (IONP) synthesis utilizing a series of imidazolium-based ionic liquids (ILs) with chloride, bis(trifluoromethylsulfonyl)imide, and pyrrolide anions as the reaction media, thus eliminating the use of volatile organics while enabling rapid synthesis at 80 °C as well as in situ surface functionalization. The characterized surface functionality, hydrodynamic particle size, magnetization, and colloidal stability of the IONPs demonstrate a strong dependence on the IL structure, ion coordination strength, reactivity, and hydrophilicity. The IONPs present primarily a magnetite (Fe3O4) phase with superparamagnetism with the highest saturation magnetization at 81 and 73 emu/g at 10 and 300 K, respectively. Depending on the IL coating, magnetization and exchange anisotropy decrease by 20 and 2–3 emu/g (at 35 wt % IL), respectively, but still represent the highest magnetization achieved for coated IONPs by a coprecipitation method. Further, the surface-functionalized superparamagnetic magnetite nanoparticles show good dispersibility and colloidal stability in water and dimethyl sulfoxide at 0.1 mg/mL concentration over the examined 3 month period. This study reports on the intermolecular and chemical interactions between the particle surface and the ILs under synthetic conditions as they relate to the magnetic and thermal properties of the resulting IONPs that are well suited for a variety of applications, including separation and catalysis.}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Cagli, Eda and Klemm, Aidan and Ali, Adam and Gai, Zheng and Unocic, Kinga A. and Kidder, Michelle K. and Gurkan, Burcu}, year={2024}, month={Apr} }
 @article{kannan_lee_pierce_unocic_fillingim_feldhausen_rossy_wang_nandwana_2023, title={Additive manufacturing as a processing route for steel-aluminum bimetallic structures}, volume={231}, ISSN={0264-1275}, url={http://dx.doi.org/10.1016/j.matdes.2023.112003}, DOI={10.1016/j.matdes.2023.112003}, abstractNote={Here we present results on the fabrication of steel-aluminum bi-metallic structures using directed energy deposition additive manufacturing. The challenges associated with the fabrication of a sharp transition from steel to aluminum are uncovered using ex-situ characterization techniques and thermo-mechanical modeling of the deposition process. It was found that the fabrication of a sharp steel-aluminum transition is challenging with extensive cracking observed at the interface. The cracking was attributed to the combined effect of residual stress development due to thermal expansion coefficient mismatch and the presence of ordered intermetallics with low ductility at the interface. Using a coupled thermodynamic and thermo-mechanical modeling approach, potential pathways to enable the fabrication of steel-aluminum bi-metallic structures using additive manufacturing are proposed. The results presented here can lay the foundation for future work on the fabrication of bi-metallic steel-aluminum structures using directed energy deposition.}, journal={Materials & Design}, publisher={Elsevier BV}, author={Kannan, Rangasayee and Lee, Yousub and Pierce, Dean and Unocic, Kinga and Fillingim, Blane and Feldhausen, Thomas and Rossy, Andres Marquez and Wang, Hsin and Nandwana, Peeyush}, year={2023}, month={Jul}, pages={112003} }
 @article{yung_mukarakate_iisa_wilson_nimlos_habas_dutta_unocic_schaidle_griffin_2023, title={Advancements and challenges in the production of low-carbon fuels <i>via</i> catalytic fast pyrolysis of biomass through refinery integration and co-product generation}, volume={25}, ISSN={1463-9262 1463-9270}, url={http://dx.doi.org/10.1039/d3gc01574b}, DOI={10.1039/D3GC01574B}, abstractNote={Creating pathways to renewable fuels, chemicals, and materials through improved catalyst formulations and integrated process development.}, number={17}, journal={Green Chemistry}, publisher={Royal Society of Chemistry (RSC)}, author={Yung, Matthew M. and Mukarakate, Calvin and Iisa, Kristiina and Wilson, A. Nolan and Nimlos, Mark R. and Habas, Susan E. and Dutta, Abhijit and Unocic, Kinga A. and Schaidle, Joshua A. and Griffin, Michael B.}, year={2023}, pages={6809–6822} }
 @article{libretto_tacey_zubair_bui_unocic_baddour_griffin_schaidle_farberow_ruddy_et al._2023, title={Compositional dependence of hydrodeoxygenation pathway selectivity for Ni<sub>2−<i>x</i></sub>Rh<sub><i>x</i></sub>P nanoparticle catalysts}, volume={11}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/d3ta02071a}, DOI={10.1039/D3TA02071A}, abstractNote={Controlled synthesis of Ni 2− x Rh x P nanoparticle catalysts enables an understanding of composition-dependent selectivity for the hydrodeoxygenation reaction of phenolic molecules.}, number={31}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={LiBretto, Nicole J. and Tacey, Sean A. and Zubair, Muhammad and Bui, Tuong V. and Unocic, Kinga A. and Baddour, Frederick G. and Griffin, Michael B. and Schaidle, Joshua A. and Farberow, Carrie A. and Ruddy, Daniel A. and et al.}, year={2023}, pages={16788–16802} }
 @article{alegre-requena_hafenstine_huo_guan_stunkel_baddour_unocic_klein_davis_paton_et al._2023, title={Experimental and computational studies of the production of 1,3-butadiene from 2,3-butanediol using SiO2-supported H3PO4 derivatives}, volume={466}, ISSN={1385-8947}, url={http://dx.doi.org/10.1016/j.cej.2023.143346}, DOI={10.1016/j.cej.2023.143346}, abstractNote={Silica-supported phosphoric acid and metal phosphate catalyzed 1,3-butadiene (BDE) production from 2,3-butanediol (2,3-BDO) was studied using experimental and computational techniques. The catalyst was initially tested in a continuous flow reactor using commercially available 2,3-BDO, leading to maximum BDE yields of 63C%. Quantum chemical mechanistic studies revealed 1,2-epoxybutane is a kinetically viable and thermodynamically stable intermediate, supported by experimental demonstration that this epoxide can be converted to BDE under standard reaction conditions. Newly proposed E2 and SN2′ elementary steps were studied to rationalize the formation of BDE and all detected side-products. Additionally, using quantum mechanics/molecular mechanics (QM/MM) calculations, we modeled silica-supported phosphate catalysts to study the effect of the alkali metal center. Natural population analysis showed that phosphate oxygen atoms are more negatively charged in CsH2PO4/SiO2 than in H3PO4/SiO2. In combination with temperature-programmed desorption experiments using CO2, the results of this study suggest that the improved selectivity achieved when adding the metal center is related to an increase in the basicity of the catalyst.}, journal={Chemical Engineering Journal}, publisher={Elsevier BV}, author={Alegre-Requena, Juan V. and Hafenstine, Glenn R. and Huo, Xiangchen and Guan, Yanfei and Stunkel, Jim and Baddour, Frederick G. and Unocic, Kinga A. and Klein, Bruno C. and Davis, Ryan E. and Paton, Robert S. and et al.}, year={2023}, month={Jun}, pages={143346} }
 @article{cramer_cakmak_unocic_2023, title={Hardness Measurements and Interface Behavior of SiC-B4C-Si Multiple Phase Particulate Composites Made with Melt Infiltration and Additive Manufacturing}, volume={7}, ISSN={2504-477X}, url={http://dx.doi.org/10.3390/jcs7040172}, DOI={10.3390/jcs7040172}, abstractNote={Reaction-bonded SiC-B4C-Si ceramic composites were binder jet 3D-printed and subsequently pressureless-melt-infiltrated with molten Si. The addition of B4C aided the Si infiltration to produce a highly dense composite. The microstructures and phases of these composites were examined. The measured hardness values of each constituent with Vickers and nanoindentation matched the bulk values, and the macro-hardness values with Knoop and spherical indentation represented the bulk, composite hardness values of all three phases together, which was close to a rule of mixtures value. For particulate-based composites, this is a significant finding. The interfacial bonds of SiC and Si were imaged using scanning transmission electron microscopy to view intimacy, whereas the crack propagation was examined with carefully placed indents. This work demonstrated that pressureless melt infiltration with a reactive particle provides a method to shape non-wetting reaction-bonded ceramic composites with limited shrinkage and high density and provides insights into the mechanical behavior with numerous indentation techniques.}, number={4}, journal={Journal of Composites Science}, publisher={MDPI AG}, author={Cramer, Corson L. and Cakmak, Ercan and Unocic, Kinga A.}, year={2023}, month={Apr}, pages={172} }
 @article{unocic_purdy_allard_collinge_zhang_borate_wu_wegener_samad_habas_et al._2023, title={Investigation of Cu Species in Dealuminated Beta Zeolite Studied by <i>Operando</i> Closed-Cell Gas Reaction STEM}, volume={29}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1093/micmic/ozad067.829}, DOI={10.1093/micmic/ozad067.829}, abstractNote={Journal Article Investigation of Cu Species in Dealuminated Beta Zeolite Studied by Operando Closed-Cell Gas Reaction STEM Get access Kinga A Unocic, Kinga A Unocic Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Corresponding author: unocicka@ornl.gov Search for other works by this author on: Oxford Academic Google Scholar Stephen C Purdy, Stephen C Purdy Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Lawrence F Allard, Lawrence F Allard Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Gregory B Collinge, Gregory B Collinge Physical and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA, USA Search for other works by this author on: Oxford Academic Google Scholar Junyan Zhang, Junyan Zhang Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Shivangi N Borate, Shivangi N Borate The University of Alabama, Tuscaloosa, Alabama, USA Search for other works by this author on: Oxford Academic Google Scholar Qiyuan Wu, Qiyuan Wu National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Evan C Wegener, Evan C Wegener Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, IL, USA Search for other works by this author on: Oxford Academic Google Scholar Nohor “River” Samad, Nohor “River” Samad The University of Alabama, Tuscaloosa, Alabama, USA Search for other works by this author on: Oxford Academic Google Scholar Susan Habas, Susan Habas National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar ... Show more Theodore R Krause, Theodore R Krause Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, IL, USA Search for other works by this author on: Oxford Academic Google Scholar James W Harris, James W Harris The University of Alabama, Tuscaloosa, Alabama, USA Search for other works by this author on: Oxford Academic Google Scholar Mal-Soon Lee, Mal-Soon Lee Physical and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA, USA Search for other works by this author on: Oxford Academic Google Scholar Vassiliki A Glezakou, Vassiliki A Glezakou Physical and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA, USAChemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Roger Rousseau, Roger Rousseau Physical and Computational Sciences, Pacific Northwest National Laboratory, Richland, WA, USAChemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Andrew D Sutton, Andrew D Sutton Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Zhenglong Li Zhenglong Li Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 1614–1615, https://doi.org/10.1093/micmic/ozad067.829 Published: 22 July 2023}, number={Supplement_1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A and Purdy, Stephen C and Allard, Lawrence F and Collinge, Gregory B and Zhang, Junyan and Borate, Shivangi N and Wu, Qiyuan and Wegener, Evan C and Samad, Nohor “River” and Habas, Susan and et al.}, year={2023}, month={Jul}, pages={1614–1615} }
 @article{lach_gussev_unocic_zhong_godfrey_mcclintock_2023, title={Multimodal Characterization of Stored Energy and Gas-Filled Cavities in FCC Alloys Irradiated with Spallation Neutrons and High-Energy Protons}, volume={29}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1093/micmic/ozad067.792}, DOI={10.1093/micmic/ozad067.792}, number={Supplement_1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Lach, Timothy G and Gussev, Maxim N and Unocic, Kinga A and Zhong, Weicheng and Godfrey, Amy and McClintock, David A}, year={2023}, month={Jul}, pages={1538–1540} }
 @article{allard_unocic_datye_mansfield_2023, title={Professor Wilbur C. Bigelow: A Centenary Celebration}, volume={29}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1093/micmic/ozad067.806}, DOI={10.1093/micmic/ozad067.806}, abstractNote={was a founding member of EMSA in 1942 (and also the second PhD student of Linus Pauling at Caltech in 1933), provided his students with access to Michigan's RCA EMB instrument, the second RCA in the world, delivered in 1940.Wil utilized this instrument to capture his first electron micrographs.After finishing his PhD in 1951, he continued at Michigan with a research appointment in the High Temperature Metallurgy group in the Department of Chemical and Metallurgical Engineering.There he used electron microscopy and diffraction methods to study precipitate phases that were developed at high temperatures in several alloys then in use in jet aircraft engines.In 1955 he joined the "Chem & Met" faculty as an assistant professor, and began teaching a microscopy course using the department's new RCA EML instrument; he was ultimately promoted to Professor of Materials Engineering in 1962.His contributions to the field were recognized early on, as he served as the Program Chair of the society's national meeting in 1960 and was a Director of Physical Sciences from 1961 to 1963, eventually leading to his election as President of the EMSA in 1969 (when the meeting was also held in Minneapolis).Wil was elected MSA Fellow in the class of 2019.In 1961-62 Wil acquired two nearly identical JEOL JEM-6A electron microscopes (replacing the EML instrument), one of which was fully equipped including a 16-mm cine camera system.He had maintained a close association with Prof. Brockway, who at around this time had, as a consultant for Oak Ridge National Laboratory, become interested in ORNL work on the oxidation behavior of bulk single crystals of copper.An example of oxide patterns on a Cu sphere from that work is shown in Fig. 1 (compare to Fig. 8 in [1]).Prof. Brockway had the idea that interesting results might be obtained by electron microscopy studies of the oxidation of 'thin' single crystal films of copper, and he acquired funding support from Oak Ridge sources to conduct oxidation studies at Michigan.After several years of learning the details of thin film preparation and oxidation in a high-vacuum benchtop reactor system, Profs.Brockway and Bigelow designed and constructed a special top-entry heating stage and gas-handling manifold system to conduct in situ oxidation studies using the JEM-6A cine camera to record dynamic experiments.The principal operator for those reaction experiments was undergraduate student Larry Allard, whom Wil trained in TEM theory and practice as a sophomore, beginning in the fall of 1963; Fig. 2a shows the gas manifold and Allard at the microscope in 1965.Fig. 2b is an image in a single cine-film frame from an oxidation run, showing faceted CuO 2 grains in an 80nm-thick <001> zone-axis film, and a stacking fault in the <110> direction Since the "best case" resolution of the microscope was specified at 1.0nm, given that the magnification needed to be significantly reduced due to the tiny size of the cine film frames, and that there were also issues such as vibrations from the hard-coupled cine camera motor which necessarily limited the useful magnification during a reaction run, the best resolution for images such as Fig. 2b was likely in the range of a several nm.In 1967, Wil acquired the university's first electron microprobe, an ARL-EMX-SM instrument, which was installed near the TEM laboratory.The microprobe was jointly associated with several university departments and became the base instrument for a central microscopy facility for the university.Wil became a charter member of the Microbeam Analysis Society when it began in 1968 (and was recently named a Legend Fellow of the society).The central facility was expanded in 1970 and thereafter with the acquisition of two JEOL JSM-U3 SEMs, and officially became known as the Electron Microbeam Analysis Laboratory (EMAL).The EMAL under Wil's direction continued expanding into other campus locations until it was split between Central Campus and North Campus locations.During this time, a number of "first" instruments were added including the university's first analytical TEM (1978) and its first surface analysis instrument, until Wil's retirement from teaching in 1993 at age 70.After retiring, Wil completed and published his book "Vacuum Methods in Electron Microscopy" in 1994 and then began consulting with ORNL and other industrial and academic institutions in the design and production of special-purpose devices for electron microscopes, completing more than 45 of those projects over the next two decades.Early projects at ORNL included the design of side-entry holders for Hitachi and JEOL microscopes to allow e.g.transfer of samples between an ex situ gas reactor he designed, and the electron microscopes, under anaerobic conditions.This experience was beneficial when the opportunity arose in 2006 to collaborate with the founders of Protochips Inc. in the development of that company's microelectromechanical systems (MEMS)-based heater technology into the capability to perform in situ heating and gas-reaction experiments within the small-gap (2 mm) objective lens pole piece in ORNL's JEOL 2200FS aberration-corrected (S)TEM instrument.Fig. 3a shows Wil's first single-tilt holder with an early MEMS heater installed, while Fig. 3b compares the "old" versus the "new" heater technology: a hand-wound heater coil for the JEM-6A embedded in a ceramic cement, and the MEMS device that heats and cools over a 1000°C temperature range in milliseconds.Advances in microscope technology over the past 50 years (e.g.aberration correction, etc.), coupled with the stability and precision control of heating holders have led to the ability to record images such as shown in Fig. 4. With closed-cell MEMS heater gas-reaction holders, atomic structure imaging in gas pressures up to a full atmosphere is}, number={Supplement_1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Allard, Lawrence F and Unocic, Kinga A and Datye, Abhaya K and Mansfield, John M}, year={2023}, month={Jul}, pages={1566–1568} }
 @article{zhou_unocic_wang_shan_haigh_yang_2023, title={Revealing atomic-to-nanoscale oxidation mechanisms of metallic materials}, volume={48}, ISSN={0883-7694 1938-1425}, url={http://dx.doi.org/10.1557/s43577-023-00595-4}, DOI={10.1557/s43577-023-00595-4}, number={8}, journal={MRS Bulletin}, publisher={Springer Science and Business Media LLC}, author={Zhou, Guangwen and Unocic, Kinga A. and Wang, Chongmin and Shan, Zhiwei and Haigh, Sarah J. and Yang, Judith C.}, year={2023}, month={Aug}, pages={852–863} }
 @article{li_zhang_purdy_lin_unocic_cordon_wu_wang_hall_kropf_et al._2024, title={Tailoring olefin distribution via tuning rare earth metals in bifunctional Cu-RE/beta-zeolite catalysts for ethanol upgrading}, volume={344}, ISSN={0926-3373}, url={http://dx.doi.org/10.1016/j.apcatb.2023.123648}, DOI={10.1016/j.apcatb.2023.123648}, abstractNote={Bioethanol to middle distillate technologies have offered a unique solution to produce renewable aviation fuel for decarbonizing the hard-to-electrify sectors. Here, we have developed the series of bimetallic Cu- and rare earth-containing (RE) Beta zeolite catalysts that yield high C3+ alkene selectivity from ethanol upgrading (>80% selectivity at ∼100% conversion, 623 K). The formation rates of butene isomers to C5+ alkenes are linearly correlated with the strength of Lewis acidic RE identity, which follows the sequence of Yb12/Beta >Y7/Beta > Gd12/Beta > Ce10/Beta > La12/Beta. Rate measurements indicate that the RE selection plays the vital role in altering the rate of the key competitive reactions within the ethanol-to-alkenes reaction network, namely C4 alcohol dehydration and C-C chain growth, which dictate alkene product distributions. These findings indicate a feasible and promising method for tailoring alkene product distributions from ethanol upgrading, which is of notable significance to the generation of renewable middle distillates.}, journal={Applied Catalysis B: Environmental}, publisher={Elsevier BV}, author={Li, Meijun and Zhang, Junyan and Purdy, Stephen C. and Lin, Fan and Unocic, Kinga A. and Cordon, Michael and Wu, Zili and Wang, Huamin and Hall, Jacklyn and Kropf, A. Jeremy and et al.}, year={2024}, month={May}, pages={123648} }
 @article{downes_van allsburg_tacey_unocic_baddour_ruddy_libretto_o’connor_farberow_schaidle_et al._2022, title={Controlled Synthesis of Transition Metal Phosphide Nanoparticles to Establish Composition-Dependent Trends in Electrocatalytic Activity}, volume={34}, ISSN={0897-4756 1520-5002}, url={http://dx.doi.org/10.1021/acs.chemmater.2c00085}, DOI={10.1021/acs.chemmater.2c00085}, abstractNote={Transition-metal phosphides (TMPs) are versatile materials with tunable electronic and structural properties that have led to exceptional catalytic performances for important energy applications. Identifying predictive relationships between the catalytic performance and key features such as the composition, morphology, and crystalline structure hinges on the ability to independently tune these variables within a TMP system. Here, we have developed a versatile, low-temperature solution synthesis route to alloyed nickel phosphide (Ni1.6M0.4P, where M = Co, Cu, Mo, Pd, Rh, or Ru) nanoparticles (NPs) that retains the structure of the parent Ni2P NPs, allowing investigation of compositional effects on activity without convoluting factors from differences in morphology and crystalline phase. As a measure of the controlled changes introduced within the isostructural series by the second metal, the binary and alloyed ternary TMP NPs supported on carbon at a nominal 5% weight loading were studied as electrocatalysts for the hydrogen evolution reaction (HER). The resultant activity of the electrocatalyst series spanned a 125 mV range in overpotential, and composition-dependent trends were investigated using density functional theory calculations on flat (0001) and corrugated (101̅0) Ni1.67M0.33P surfaces. Applying the adsorption free energy of atomic H (GH) as a descriptor for HER activity revealed a facet-dependent volcano-shaped correlation between the overpotential and GH, with the activity trend well represented by the corrugated (101̅0) surfaces on which metal–metal bridge sites are available for H adsorption but not the flat (0001) surfaces. The versatility of the rational synthetic methodology allows for the preparation of a wide range of compositionally diverse TMP NPs, enabling the investigation of critical composition–performance relationships for energy applications.}, number={14}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Downes, Courtney A. and Van Allsburg, Kurt M. and Tacey, Sean A. and Unocic, Kinga A. and Baddour, Frederick G. and Ruddy, Daniel A. and LiBretto, Nicole J. and O’Connor, Max M. and Farberow, Carrie A. and Schaidle, Joshua A. and et al.}, year={2022}, month={Jul}, pages={6255–6267} }
 @article{talukdar_meyer_mukarakate_iisa_griffin_habas_unocic_2022, title={Deactivation study on zeolite materials using XPS and STEM characterization}, volume={28}, ISSN={1435-8115 1431-9276}, url={http://dx.doi.org/10.1017/s1431927622009461}, DOI={10.1017/s1431927622009461}, abstractNote={Journal Article Deactivation study on zeolite materials using XPS and STEM characterization Get access Biva Talukdar, Biva Talukdar Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Harry M Meyer, III, Harry M Meyer, III Chemical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Calvin Mukarakate, Calvin Mukarakate National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Kristiina Iisa, Kristiina Iisa National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Michael B Griffin, Michael B Griffin National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Susan E Habas, Susan E Habas Chemical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Kinga A Unocic Kinga A Unocic Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Corresponding author: unocicka@ornl.gov Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 28, Issue S1, 1 August 2022, Pages 2472–2474, https://doi.org/10.1017/S1431927622009461 Published: 01 August 2022}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Talukdar, Biva and Meyer, Harry M, III and Mukarakate, Calvin and Iisa, Kristiina and Griffin, Michael B and Habas, Susan E and Unocic, Kinga A}, year={2022}, month={Aug}, pages={2472–2474} }
 @article{adhikari_zhang_unocic_wegener_kunal_deka_toops_sinha majumdar_krause_liu_et al._2022, title={Direct 2,3-Butanediol Conversion to Butene-Rich C<sub>3+</sub> Olefins over Copper-Modified 2D Pillared MFI: Consequence of Reduced Diffusion Length}, volume={10}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.1c07670}, DOI={10.1021/acssuschemeng.1c07670}, abstractNote={2,3-Butanediol (2,3-BDO), a critical C4 platform chemical derived from biomass, syngas, or CO2, can be converted to C3+ olefins, serving as important renewable feedstocks for producing sustainable aviation fuels to decarbonize the hard-to-electrify air transportation sector. Herein, we report a bifunctional Cu-modified diffusion-free 2D pillared MFI catalyst (Cu/PMFI) which can selectively catalyze 2,3-BDO conversion to butene-rich C3+ olefins (95% selectivity at 97% conversion, 523 K). 2,3-BDO conversion to butenes over Cu/PMFI primarily occurs via methyl ethyl ketone intermediate while 2-methyl propanal is also observed as another minor dehydration product that leads to butene formation. In comparison with a control mesoporous Cu/ZSM-5 sample prepared by the postsynthetic approach, Cu/PMFI shows favorable C3+ olefin selectivity (95% over Cu/PMFI vs 80% over Cu/ZSM-5 at ∼5.1 h TOS). The coke formation over Cu/PMFI is dramatically suppressed by >50% in contrast to Cu/ZSM-5 in 90 h 2,3-BDO conversion due to the reduced diffusion length. Cu/PMFI also favors butene formation and minimizes nonbutene C3+ olefins by inhibiting the downstream oligomerization and cracking reactions. This study highlights the usefulness of the diffusion-free 2D PMFI materials in catalytic conversion of biomass-derived platform molecules and the significance of diffusion impact on catalyst coke formation and product distributions.}, number={4}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Adhikari, Shiba and Zhang, Junyan and Unocic, Kinga and Wegener, Evan C. and Kunal, Pranaw and Deka, Dhruba J. and Toops, Todd and Sinha Majumdar, Sreshtha and Krause, Theodore R. and Liu, Dongxia and et al.}, year={2022}, month={Jan}, pages={1664–1674} }
 @article{cordon_zhang_samad_harris_unocic_li_liu_li_2022, title={Ethanol Conversion to C<sub>4+</sub> Olefins over Bimetallic Copper- And Lanthanum-Containing Beta Zeolite Catalysts}, volume={10}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.1c07442}, DOI={10.1021/acssuschemeng.1c07442}, abstractNote={Ethanol conversion to C4+ olefins remains a critical yet nonselective process for producing renewable middle distillates. Here, Cu–La/Beta catalysts composed of copper and lanthanum incorporated onto a dealuminated Beta support are reported for ethanol conversion to C4+ olefins (73% selectivity, ∼98% ethanol conversion, 623 K,<4% C1–C3 hydrocarbons) which particularly favors C5+ olefin formation (43% selectivity) as a distinction from the benchmarking Cu–Y/Beta catalyst. Monometallic Cu/Beta or La/Beta samples are insufficient to catalyze the C4+ olefin formation and primarily form dehydration products (e.g., ethylene and diethyl ether), indicating the necessity of both Cu and La species for butene and C5+ olefin formation. Increasing the bulk La loading at a fixed Cu content yields higher C5+ olefins until the La/Cu molar ratio reaches 3.6. These findings indicate Cu–La/Beta as an effective ethanol conversion catalyst that facilitates multiple C–C bond formation events required for synthesizing C5+ olefins (i.e., hexenes and octenes).}, number={18}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Cordon, Michael J. and Zhang, Junyan and Samad, Nohor “River” and Harris, James W. and Unocic, Kinga A. and Li, Meijun and Liu, Dongxia and Li, Zhenglong}, year={2022}, month={Apr}, pages={5702–5707} }
 @article{dryepondt_nandwana_unocic_kannan_fernandez zelaia_list_2022, title={High temperature high strength austenitic steel fabricated by laser powder-bed fusion}, volume={231}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2022.117876}, DOI={10.1016/j.actamat.2022.117876}, abstractNote={Extremely fast cooling rates during laser powder-bed fusion (LPBF) can result in materials with unique microstructures. For LPBF 316L stainless steel, the formation of sub-grain cellular structures with high dislocation density has been linked to superior tensile properties at room temperature. This cellular structure offers also a new route for the development of high temperature LPBF steels with the nucleation of nano-size strengthening carbides in the cell walls. HK30Nb steel (Fe-25Cr-20Ni-Nb-C) was, therefore, fabricated by LPBF to evaluate its potential for high temperature applications. Optimization of the fabrication parameters yielded material with density greater than 99.7%, with nano Nb-rich precipitates in the cell walls. Annealing at 800 °C for 5h resulted in the nucleation and growth of additional precipitates mainly in the cell walls and at grain boundaries. The high dislocation density led to yield strength at 20–900 °C two to three times higher than yield strength for cast HK30Nb and the nano carbides in the cell walls significantly improved the cellular structure stability at 800 °C.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Dryepondt, Sebastien and Nandwana, Peeyush and Unocic, Kinga A. and Kannan, Rangasayee and Fernandez Zelaia, Patxi and List, Fred A., III}, year={2022}, month={Jun}, pages={117876} }
 @article{mao_massey_yamamoto_unocic_gussev_zhang_briggs_karakoc_nelson_field_et al._2022, title={Improved irradiation resistance of accident-tolerant high-strength FeCrAl alloys with heterogeneous structures}, volume={231}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2022.117843}, DOI={10.1016/j.actamat.2022.117843}, abstractNote={Post–neutron irradiation examination is performed on advanced accident-tolerant fuel (ATF) cladding iron-chromium-aluminum (FeCrAl) alloys with ∼10–13at. % Cr, ∼10–12 at. % Al, ∼1 at. % Mo, and minor alloying elements including Y irradiated to a damage level of 7 displacements per atom (dpa) at irradiation temperatures of 267–282 °C. A compositional dependency of the Cr and Al content is observed on the ratio of sessile and glissile dislocation loops, where the density of a⟨100⟩ type loops is somewhat higher than the a/2⟨111⟩ type loops. The α′ precipitate number density is inversely correlated to the starting Cr concentration of the alloys of interest. The irradiation to a higher dose of 7 dpa results in a higher density of dislocation loops and α′ precipitates for the same alloys at a lower irradiation dose, such as 1.8 dpa. In this work, the effect of α′ precipitates on the dislocation loop density is discussed, and the presence of α′ appears to inhibit the nucleation of loops. Compared with first-generation FeCrAl alloys, these advanced alloys with heterogeneous structure exhibit a lower Cr concentration in α′ precipitation at the same dose level; they act as weaker obstacles deviating from the primary hardening contribution from the mature α′. Hence, the overall irradiation-induced hardening decreases; our alloys show improved radiation resistance because of their stronger sink strengths. The results presented in this paper could provide insights for the design and optimization of ATF cladding materials for future fission and space applications.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Mao, Keyou S. and Massey, Caleb P. and Yamamoto, Yukinori and Unocic, King A. and Gussev, Maxim N. and Zhang, Dalong and Briggs, Samuel A. and Karakoc, Omer and Nelson, Andrew T. and Field, Kevin G. and et al.}, year={2022}, month={Jun}, pages={117843} }
 @article{mcclintock_gussev_campbell_mao_lach_lu_hachtel_unocic_2022, title={Observations of radiation-enhanced ductility in irradiated Inconel 718: Tensile properties, deformation behavior, and microstructure}, volume={231}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2022.117889}, DOI={10.1016/j.actamat.2022.117889}, abstractNote={An increase in ductility with radiation dose was observed and investigated during postirradiation evaluation of tensile properties, microstructure, deformation behavior, and fracture behavior of specimens from a solution-annealed Inconel 718 proton beam window operated at the Spallation Neutron Source. While in service, the window was irradiated with 940 MeV protons to a maximum dose of approximately 9.7 displacements per atom (dpa) at a calculated irradiation temperature of approximately 110 °C. The double-walled window was sampled after removal from service, and specimens from the samples were characterized using transmission electron microscopy and tensile testing accompanied by digital image correlation. The results showed that the window material had very high tensile strength and retained an appreciable amount of ductility after irradiation. Specimens irradiated to approximately 9 dpa had yield strengths of around 1 GPa while concurrently straining to approximately 19% total elongation before fracture. A steady increase in ductility was observed with increasing dose for the material tested; both uniform and total elongation values increased as the radiation dose increased from 2.5 to 9.7 dpa. High-resolution scanning transmission electron microscopy and electron energy-loss spectroscopy, performed at atomic resolution, showed the existence of nanometer scale stacking faults and nanometer size vacancy clusters associated with H and possibly He. These radiation-induced defect structures may have increased the ability of the material to strain-harden during deformation and increased the ductility with increasing dose. The results were encouraging and suggest that the mechanical performance of Inconel 718 after irradiation to 9.7 dpa is favorable and provided support to increase the proton beam window service lifetime to higher displacement dose levels.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={McClintock, David A. and Gussev, Maxim N. and Campbell, Cody and Mao, Keyou and Lach, Timothy G. and Lu, Wei and Hachtel, Jordan A. and Unocic, Kinga A.}, year={2022}, month={Jun}, pages={117889} }
 @article{unocic_libretto_to_kropf_ruddy_krause_allard_habas_2022, title={Revealing the Reaction Behavior of Co0.86Mn0.14O under H2 using <i>in situ</i> Closed-Cell Gas Reaction S/TEM}, volume={28}, ISSN={1435-8115 1431-9276}, url={http://dx.doi.org/10.1017/s1431927622007395}, DOI={10.1017/s1431927622007395}, abstractNote={Journal Article Revealing the Reaction Behavior of Co0.86Mn0.14O under H2 using in situ Closed-Cell Gas Reaction S/TEM Get access Kinga A Unocic, Kinga A Unocic Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Corresponding author: unocicka@ornl.gov Search for other works by this author on: Oxford Academic Google Scholar Nicole LiBretto, Nicole LiBretto National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Anh T To, Anh T To National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Jeremy A Kropf, Jeremy A Kropf Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, IL, USA Search for other works by this author on: Oxford Academic Google Scholar Daniel A Ruddy, Daniel A Ruddy National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Theodore R Krause, Theodore R Krause Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, IL, USA Search for other works by this author on: Oxford Academic Google Scholar Lawrence F Allard, Lawrence F Allard Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Susan E Habas Susan E Habas National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 28, Issue S1, 1 August 2022, Pages 1884–1886, https://doi.org/10.1017/S1431927622007395 Published: 01 August 2022}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A and LiBretto, Nicole and To, Anh T and Kropf, Jeremy A and Ruddy, Daniel A and Krause, Theodore R and Allard, Lawrence F and Habas, Susan E}, year={2022}, month={Aug}, pages={1884–1886} }
 @article{nguyen_huq_stück_tifft_conklin_koehler_mcneary_fioroni_hays_christensen_et al._2022, title={Supercritical Methanol Solvolysis and Catalysis for the Conversion of Delignified Woody Biomass into Light Alcohol Gasoline Bioblendstock}, volume={6}, ISSN={2366-7486 2366-7486}, url={http://dx.doi.org/10.1002/adsu.202100310}, DOI={10.1002/adsu.202100310}, abstractNote={Abstract Supercritical methanol (SCM) solvolysis and catalysis has recently emerged as a promising pathway to produce gasoline‐range light alcohols from woody biomass through staged depolymerization and hydro‐deoxygenation (DHDO). Here, structure–property relationships of Cu“M”AlO x catalysts (M = Mg, Zr, and Ce) are examined for upgrading delignified hybrid poplar via SCM‐DHDO. CuCeAlO x displays the highest activity, increasing the C 2 C 7 alcohol production rate and selectivity by twofold in batch reactions, and > 50% in semicontinuous reactions relative to the current state‐of‐the‐art CuMgAlO x . The performance of CuCeAlO x is correlated with its high reducibility and acidity. Cu sintering and biogenic impurity poisoning are identified as possible deactivation mechanisms over 60 h of continuous testing. The gasoline‐range SCM‐DHDO products are comprised of primarily aliphatic alcohols that result in improved energy density and favorably reduced vapor pressure, relative to ethanol, with the tradeoff of nonsynergistic octane blending with conventional gasoline and lower oxidation stability. Overall, this work highlights the potential to produce suitable light oxygenates by SCM‐DHDO processing for gasoline bioblendstock applications.}, number={4}, journal={Advanced Sustainable Systems}, publisher={Wiley}, author={Nguyen, Hannah and Huq, Nabila A. and Stück, Daniela and Tifft, Stephen M. and Conklin, Davis R. and Koehler, Andrew J. and McNeary, William Wilson and Fioroni, Gina M. and Hays, Cameron and Christensen, Earl D. and et al.}, year={2022}, month={Jan} }
 @article{cavin_ahmadiparidari_majidi_thind_misal_prajapati_hemmat_rastegar_beukelman_singh_et al._2021, title={2D High‐Entropy Transition Metal Dichalcogenides for Carbon Dioxide Electrocatalysis}, volume={33}, ISSN={0935-9648 1521-4095}, url={http://dx.doi.org/10.1002/adma.202100347}, DOI={10.1002/adma.202100347}, abstractNote={Abstract High‐entropy alloys combine multiple principal elements at a near equal fraction to form vast compositional spaces to achieve outstanding functionalities that are absent in alloys with one or two principal elements. Here, the prediction, synthesis, and multiscale characterization of 2D high‐entropy transition metal dichalcogenide (TMDC) alloys with four/five transition metals is reported. Of these, the electrochemical performance of a five‐component alloy with the highest configurational entropy, (MoWVNbTa)S 2 , is investigated for CO 2 conversion to CO, revealing an excellent current density of 0.51 A cm −2 and a turnover frequency of 58.3 s −1 at ≈ −0.8 V versus reversible hydrogen electrode. First‐principles calculations show that the superior CO 2 electroreduction is due to a multi‐site catalysis wherein the atomic‐scale disorder optimizes the rate‐limiting step of CO desorption by facilitating isolated transition metal edge sites with weak CO binding. 2D high‐entropy TMDC alloys provide a materials platform to design superior catalysts for many electrochemical systems.}, number={31}, journal={Advanced Materials}, publisher={Wiley}, author={Cavin, John and Ahmadiparidari, Alireza and Majidi, Leily and Thind, Arashdeep Singh and Misal, Saurabh N. and Prajapati, Aditya and Hemmat, Zahra and Rastegar, Sina and Beukelman, Andrew and Singh, Meenesh R. and et al.}, year={2021}, month={Aug} }
 @article{fuchs_qu_kim_unocic_guo_ramuhalli_jacobs_2021, title={Analytical modeling of the evolution of the nonlinearity parameter of sensitized stainless steel}, volume={130}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/5.0053632}, DOI={10.1063/5.0053632}, abstractNote={Austenitic stainless steels are subject to the precipitation of chromium carbides (M23C6) during exposure to high temperatures, causing these alloys to be susceptible to intergranular corrosion due to chromium depletion along grain boundaries. The acoustic nonlinearity parameter, β, shows sensitivity to the formation of carbides in these alloys. The Thermo-Calc TC-PRISMA module was used to model the nucleation and growth of grain boundary M23C6 carbides. The model was verified with scanning transmission electron microscopy analysis that allowed measurements of the grain boundary precipitates. The paper introduces a reduced-order model of the acoustic nonlinearity based on the formation of misfit dislocations at the interface of the grain boundary precipitate and matrix to explain the change in β during isothermal aging. A direct relationship between the radius of the M23C6 grain boundary carbides and β was observed and verified with nonlinear ultrasound measurements on 304L and 316L stainless steels.}, number={16}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Fuchs, Brian and Qu, Jianmin and Kim, Jin-Yeon and Unocic, Kinga A. and Guo, Qianying and Ramuhalli, Pradeep and Jacobs, Laurence J.}, year={2021}, month={Oct} }
 @article{mcneary_tacey_lahti_conklin_unocic_tan_wegener_erden_moulton_gump_et al._2021, title={Atomic Layer Deposition with TiO<sub>2</sub> for Enhanced Reactivity and Stability of Aromatic Hydrogenation Catalysts}, volume={11}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.1c02101}, DOI={10.1021/acscatal.1c02101}, abstractNote={Hydrogenation of aromatic molecules in fossil- and bio-derived fuels is essential for decreasing emissions of harmful combustion products and addressing growing concerns around urban air pollution. In this work, we used atomic layer deposition to significantly enhance the hydrogenation performance of a conventional supported Pd catalyst by applying an ultrathin coating of TiO2 in a scalable powder coating process. The TiO2-coated catalyst showed substantial gains in the conversion of multiple aromatic molecules, including a 5-fold improvement in turnover frequency versus the uncoated catalyst in the hydrogenation of naphthalene. This activity enhancement was maintained upon scaling the coating synthesis process from 3 to 100 g. Based on the results from X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and computational modeling, the activity enhancement was attributed to ensemble effects resulting from partial TiO2 coverage of the Pd surface rather than fundamental changes to the Pd electronic structure. Additional durability testing confirmed that the TiO2 coating improved the thermal and hydrothermal stability of the catalyst as well as tolerance toward sulfur impurities in the reactant stream. Using an economic model of an industrial deep hydrogenation process, we found that an increase in catalyst activity or lifetime of 2× would justify even a relatively high estimate for the cost of TiO2 atomic layer deposition coatings at scale.}, number={14}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={McNeary, W. Wilson and Tacey, Sean A. and Lahti, Gabriella D. and Conklin, Davis R. and Unocic, Kinga A. and Tan, Eric C. D. and Wegener, Evan C. and Erden, Tugce Eralp and Moulton, Staci and Gump, Chris and et al.}, year={2021}, month={Jun}, pages={8538–8549} }
 @article{nash_dupuis_kumar_farberow_to_yang_wegener_miller_unocic_christensen_et al._2022, title={Catalyst design to direct high-octane gasoline fuel properties for improved engine efficiency}, volume={301}, ISSN={0926-3373}, url={http://dx.doi.org/10.1016/j.apcatb.2021.120801}, DOI={10.1016/j.apcatb.2021.120801}, abstractNote={The paraffin-to-olefin (P/O) ratio in gasoline fuel is a critical metric affecting fuel properties and engine efficiency. In the conversion of dimethyl ether (DME) to high-octane hydrocarbons over BEA zeolite catalysts, the P/O ratio can be controlled through catalyst design. Here, we report bimetallic catalysts that balance the net hydrogenation and dehydrogenation activity during DME homologation. The Cu-Zn/BEA catalyst exhibited greater relative dehydrogenation activity attributed to higher ionic site density, resulting in a lower P/O ratio (6.6) versus the benchmark Cu/BEA (9.4). The Cu-Ni/BEA catalyst exhibited increased hydrogenation due to reduced Ni species, resulting in a higher P/O ratio (19). The product fuel properties were estimated with an efficiency merit function and compared against finished gasolines and a typical alkylate blendstock. Merit values for the hydrocarbon product from all three BEA catalysts exceeded those of the comparison fuels (0–5.3), with the product from Cu-Zn/BEA exhibiting the highest merit value (9.7).}, journal={Applied Catalysis B: Environmental}, publisher={Elsevier BV}, author={Nash, Connor P. and Dupuis, Daniel P. and Kumar, Anurag and Farberow, Carrie A. and To, Anh T. and Yang, Ce and Wegener, Evan C. and Miller, Jeffrey T. and Unocic, Kinga A. and Christensen, Earl and et al.}, year={2022}, month={Feb}, pages={120801} }
 @article{huo_conklin_zhou_vorotnikov_assary_purdy_page_li_unocic_balderas_et al._2021, title={Catalytic activity and water stability of the MgO(111) surface for 2-pentanone condensation}, volume={294}, ISSN={0926-3373}, url={http://dx.doi.org/10.1016/j.apcatb.2021.120234}, DOI={10.1016/j.apcatb.2021.120234}, abstractNote={Nanomaterials derived from earth-abundant metal oxides have gained tremendous interest as catalysts; although, water stability remains a challenge. This study examines MgO(111) surfaces for 2-pentanone condensation and their evolution during D2O hydration. Catalyst screening confirmed the high activity of fresh MgO(111) for 2-pentanone condensation relative to conventionally prepared MgO(100). Computational modeling suggests that the (111) surface is readily hydroxylated, and that surface hydroxyls help stabilize the surface and reduce the barrier for 2-pentanone condensation. Vapor-phase D2O hydration after 3 min increased MgO(111) hydroxyls and retained surface area and activity; however, after 1 h, deuteroxide formation reduced the surface area and activity by >30 %. After 24 h, deuteroxide growth slowed down, and surface area and activity remained stable. This suggests MgO(111)-derived hydroxide may be the dominant surface responsible for 2-pentanone condensation following water exposure. Thermal regeneration of the 24-h sample restored 86 % of the surface area and 94 % of the activity.}, journal={Applied Catalysis B: Environmental}, publisher={Elsevier BV}, author={Huo, Xiangchen and Conklin, Davis R. and Zhou, Mingxia and Vorotnikov, Vassili and Assary, Rajeev S. and Purdy, Stephen C. and Page, Katharine and Li, Zhenglong and Unocic, Kinga A. and Balderas, Raiven I. and et al.}, year={2021}, month={Oct}, pages={120234} }
 @article{lin_lu_unocic_habas_griffin_schaidle_meyer_wang_wang_2021, title={Deactivation by Potassium Accumulation on a Pt/TiO<sub>2</sub> Bifunctional Catalyst for Biomass Catalytic Fast Pyrolysis}, volume={12}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.1c02368}, DOI={10.1021/acscatal.1c02368}, abstractNote={Biomass-derived feedstocks bring significant challenges to the longevity of the catalysts used for their conversion, and alkali metals, for example, K, in the feedstock have been widely ascribed as one of the important factors causing catalyst deactivation. To address this challenge, it is critical to understand the mechanism of catalyst deactivation caused by K accumulation to guide the improvement of catalysts and processes and the development of catalyst regeneration strategies. In this work, we report a deep understanding of the impact of K on a bifunctional Pt/TiO2 catalyst, which is an efficient catalyst for the ex situ catalytic fast pyrolysis of biomass. We simulated the K-poisoning of Pt/TiO2 catalysts by purposely loading different amounts of K (100–6000 ppm by weight) on the catalysts. A series of characterization approaches, including scanning transmission electron microscopy, Fourier transform infrared spectroscopy, and chemical titration, were combined with a kinetic assessment of multiple probe reactions to elucidate the mechanism of Pt/TiO2 deactivation by K accumulation. At low K loadings (<800 ppm), K preferentially poisons the strong Lewis acid sites, leading to significantly reduced activity for acid-catalyzed alcohol dehydration. However, acetone condensation is less sensitive to the poisoning of strong Lewis acid sites. Reactions that occur on Pt sites or at the metal–support interface, including alkene hydrogenation, m-cresol hydrodeoxygenation (HDO), and CO oxidation, were not impacted. At high K loadings (>800 ppm), K starts to accumulate on the Pt–TiO2 interfacial area, poisoning the interfacial active sites for HDO and CO oxidation reactions. We further found that the poisoning of the Pt/TiO2 catalyst by K is reversible, and water washing can successfully remove the accumulated K and recover the activities for both alcohol dehydration and m-cresol HDO reactions.}, number={1}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Lin, Fan and Lu, Yubing and Unocic, Kinga A. and Habas, Susan E. and Griffin, Michael B. and Schaidle, Joshua A. and Meyer, Harry M., III and Wang, Yong and Wang, Huamin}, year={2021}, month={Dec}, pages={465–480} }
 @article{wang_mao_tortorelli_maziasz_thangirala_unocic_chen_2021, title={Effect of heterogeneous microstructure on the tensile and creep performances of cast Haynes 282 alloy}, volume={828}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/j.msea.2021.142099}, DOI={10.1016/j.msea.2021.142099}, abstractNote={Precipitation-strengthened Ni-based superalloys are leading candidate materials for advanced ultra-supercritical (A-USC) plants with steam conditions up to 760 °C (1400 °F) and 35 MPa (5 ksi). This study evaluates representative specimens from a large casting of Haynes 282 to study the effect of microstructural heterogeneity on the mechanical behavior of this alloy. The tensile test results of cast Haynes 282 over the temperature range 20–816 °C exhibited lower tensile strength and ductility in comparison with the reference wrought Haynes 282. However, the creep rupture tests of the cast alloy below 704–788 °C and 190–431 MPa presented a similar stress-Larson-Miller parameter to that of the wrought material. Microstructural and dislocation characterizations using scanning electron microscopy, conventional transmission electron microscopy, and scanning transmission electron microscopy in conjunction with energy dispersive X-ray spectroscopy were performed to understand the microstructural evolution before and after the mechanical tests. The heterogeneous microstructures of the cast Haynes 282 material, including the coarse grains, potential casting defects, and a bimodal size distribution of γ′ precipitates, were detrimental to the tensile behavior, whereas the coarse-scale grains had a positive effect on the creep performance because diffusional creep was the dominant creep mechanism.}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Wang, Ling and Mao, Keyou and Tortorelli, Peter F. and Maziasz, Philip J. and Thangirala, Mani and Unocic, Kinga A. and Chen, Xiang Frank}, year={2021}, month={Nov}, pages={142099} }
 @article{guo_feng_lance_unocic_pantelides_lara-curzio_2022, title={Evolution of the structure and chemical composition of the interface between multi-component silicate glasses and yttria-stabilized zirconia after 40,000 h exposure in air at 800 °C}, volume={42}, ISSN={0955-2219}, url={http://dx.doi.org/10.1016/j.jeurceramsoc.2021.11.013}, DOI={10.1016/j.jeurceramsoc.2021.11.013}, abstractNote={The chemical and structural stability of two commercial multicomponent silicate glasses (SCN and G6) in contact with yttria-stabilized zirconia (YSZ) was investigated after exposure times of up to 40,000 h in air at 800 °C. With exposure time, interfacial layers develop at the SCN-YSZ and G6-YSZ interfaces, which were characterized in detail using both quantitative chemical analysis and atomic-resolution imaging. At the SCN-YSZ interface, a Ca-Ba-Si-O reaction phase was found to grow by diffusion control. In G6-YSZ, Raman spectroscopy and electron microscopy revealed a disorganized interfacial reaction later between G6 and YSZ, and the occurrence of cubic to tetragonal to monoclinic phase transformations in YSZ. This microstructural evolution is discussed in terms of devitrification resistance of glass and diffusion processes at interfaces.}, number={4}, journal={Journal of the European Ceramic Society}, publisher={Elsevier BV}, author={Guo, Qianying and Feng, Tianli and Lance, Michael J. and Unocic, Kinga A. and Pantelides, Sokrates T. and Lara-Curzio, Edgar}, year={2022}, month={Apr}, pages={1576–1584} }
 @article{boebinger_yarema_yarema_unocic_unocic_wood_mcdowell_2021, title={In Situ TEM Investigation of the Spontaneous Hollowing of Alloy Anode Nanocrystals}, volume={27}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927621007170}, DOI={10.1017/s1431927621007170}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Boebinger, Matthew and Yarema, Olesya and Yarema, Maksym and Unocic, Kinga and Unocic, Raymond and Wood, Vanessa and McDowell, Matthew}, year={2021}, month={Jul}, pages={1972–1973} }
 @article{zhang_wegener_samad_harris_unocic_allard_purdy_adhikari_cordon_miller_et al._2021, title={Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C<sub>3+</sub> Olefin Formation from Ethanol}, volume={11}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.1c02177}, DOI={10.1021/acscatal.1c02177}, abstractNote={Direct and selective production of C3+ olefins from bioethanol remains a critical challenge and important for the production of renewable transportation fuels such as aviation biofuels. Here, we report a Cu–Zn–Y/Beta catalyst for selective ethanol conversion to butene-rich C3+ olefins (88% selectivity at 100% ethanol conversion, 623 K), where the Cu, Zn, and Y sites are all highly dispersed. The ethanol-to-butene reaction network includes ethanol dehydrogenation, aldol condensation to crotonaldehyde, and hydrogenation to butyraldehyde, followed by further hydrogenation and dehydration reactions to form butenes. Cu sites play a critical role in promoting hydrogenation of the crotonaldehyde C═C bond to form butyraldehyde in the presence of hydrogen, making this a distinctive pathway from crotyl alcohol-based ethanol-to-butadiene reaction. Reaction rate measurements in the presence of ethanol and acetaldehyde (543 K, 12 kPa ethanol, 1.2 kPa acetaldehyde, 101.9 kPa H2) over monometallic Zn/Beta and Y/Beta catalysts indicate that Y sites have higher C–C coupling rates than over Zn sites (initial C–C coupling rate, 6.1 × 10–3 mol molY–1 s–1 vs 1.2 × 10–3 mol molZn–1 s–1). Further, Lewis-acidic Y-site densities over Cu–Zn–Y/Beta with varied Y loadings are linearly correlated with the initial C–C coupling rates, suggesting that Lewis-acidic Y sites are the predominant sites that catalyze C–C coupling in Cu–Zn–Y/Beta catalysts. Control experiments show that the dealuminated Beta support is important to form higher density of Lewis-acidic Y sites in comparison with other supports such as silica, or deboronated MWW despite similar atomic dispersion of Y sites and Y–O coordination numbers over these supports, leading to more than 9 times higher C–C coupling rate per mole Y over dealuminated Beta relative to other supports. This study highlights the significance of unique combination of metal sites in contributing to the selective valorization of ethanol to C3+ olefins, motivating for exploring multifunctional zeolite catalysts, where the presence of multiple sites with varying reactivities and functions allows for controlling the predominant molecular fluxes toward the desired products in complex reactions.}, number={15}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Zhang, Junyan and Wegener, Evan C. and Samad, Nohor River and Harris, James W. and Unocic, Kinga A. and Allard, Lawrence F. and Purdy, Stephen and Adhikari, Shiba and Cordon, Michael J. and Miller, Jeffrey T. and et al.}, year={2021}, month={Jul}, pages={9885–9897} }
 @article{guo_watkins_trofimov_wang_cola_muth_singh_thomas_babu_unocic_2021, title={Microstructure Evolution of Low Carbon Steel via Flash Processing}, volume={27}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927621001173}, DOI={10.1017/s1431927621001173}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the 'Save PDF' action button.}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Guo, Qianying and Watkins, Thomas R. and Trofimov, Artem and Wang, Hsin and Cola, Gary and Muth, Thomas R. and Singh, Dileep and Thomas, Jonova and Babu, Sudarsanam and Unocic, Kinga A.}, year={2021}, month={Jul}, pages={156–158} }
 @article{unocic_hensley_walden_bigelow_griffin_habas_unocic_allard_2021, title={Performing <em>In Situ</em> Closed-Cell Gas Reactions in the Transmission Electron Microscope}, volume={7}, ISSN={1940-087X}, url={http://dx.doi.org/10.3791/62174}, DOI={10.3791/62174}, abstractNote={Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at length scales down to the atomic level. In situ closed-cell gas reaction (CCGR) studies performed using (scanning) transmission electron microscopy (STEM) can separate and identify localized dynamic reactions, which are extremely challenging to capture using other characterization techniques. For these experiments, we used a CCGR holder that utilizes microelectromechanical systems (MEMS)-based heating microchips (hereafter referred to as "E-chips"). The experimental protocol described here details the method for performing in situ gas reactions in dry and wet gases in an aberration-corrected STEM. This method finds relevance in many different materials systems, such as catalysis and high-temperature oxidation of structural materials at atmospheric pressure and in the presence of various gases with or without water vapor. Here, several sample preparation methods are described for various material form factors. During the reaction, mass spectra obtained with a residual gas analyzer (RGA) system with and without water vapor further validates gas exposure conditions during reactions. Integrating an RGA with an in situ CCGR-STEM system can, therefore, provide critical insight to correlate gas composition with the dynamic surface evolution of materials during reactions. In situ/operando studies using this approach allow for detailed investigation of the fundamental reaction mechanisms and kinetics that occur at specific environmental conditions (time, temperature, gas, pressure), in real-time, and at high spatial resolution.}, number={173}, journal={Journal of Visualized Experiments}, publisher={MyJove Corporation}, author={Unocic, Kinga A. and Hensley, Dale K. and Walden, Franklin S. and Bigelow, Wilbur C. and Griffin, Michael B. and Habas, Susan E. and Unocic, Raymond R. and Allard, Lawrence F.}, year={2021}, month={Jul} }
 @article{unocic_griffin_schaidle_habas_walden_unocic_allard_2021, title={Practical Aspects of Performing Quantitive EELS Measurements of Gas Compositions in Closed-Cell Gas Reaction S/TEM}, volume={27}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927621003160}, DOI={10.1017/s1431927621003160}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga and Griffin, Michael and Schaidle, Joshua and Habas, Susan and Walden, Franklin and Unocic, Raymond and Allard, Lawrence}, year={2021}, month={Jul}, pages={796–798} }
 @article{wang_unocic_tortorelli_santella_chen_2021, title={Precipitation behavior near shrinkage porosity in a large sand casting of Haynes 282 alloy}, volume={15}, ISSN={2589-1529}, url={http://dx.doi.org/10.1016/j.mtla.2021.101035}, DOI={10.1016/j.mtla.2021.101035}, abstractNote={The precipitation behavior of L12 structure Ni3(Al,Ti)-type γ' precipitates near shrinkage porosity in a large sand casting of Haynes 282 alloy has been investigated by scanning/transmission electron microscopy in conjunction with energy dispersive x-ray spectroscopy. The experimental results revealed that in the carbonitride-rich region close to the shrinkage porosity, γ' precipitates could still form with comparable sizes though at lower volume density than those in the general cast Ni matrix. The resulting γ' precipitates had a very high Al/Ti ratio. Close to oxide-rich pore surfaces, an absence of γ' precipitates was observed due to Al and Ti depletion by forming Al oxides and Ti carbonitrides, respectively. This work suggests that Al rather than Ti plays a dominant role in the formation of γ' precipitates in porous regions in cast Haynes 282 alloys.}, journal={Materialia}, publisher={Elsevier BV}, author={Wang, Ling and Unocic, Kinga A. and Tortorelli, Peter F. and Santella, Michael and Chen, Xiang  (Frank)}, year={2021}, month={Mar}, pages={101035} }
 @article{watkins_unocic_peralta_megahed_bunn_fancher_d'elia_hill_neumann_2021, title={Residual stresses and microstructure within Allvac 718Plus laser powder bed fusion bars}, volume={47}, ISSN={2214-8604}, url={http://dx.doi.org/10.1016/j.addma.2021.102334}, DOI={10.1016/j.addma.2021.102334}, abstractNote={The residual stresses within Allvac 718Plus bars built using LBPF with different laser powers, speeds and table displacements were measured using diffraction and mechanical methods and modelled with the baseplate attached and then removed. The residual stress profiles within the bars from the top surface down through the bulk were all quite similar, becoming less tensile due to a strain hardening mechanism. Table displacement has the greatest impact on residual stress, decreasing with increasing displacement/powder layer thickness. There was good agreement amongst the modeling and measurements. The microstructures were examined and varied slightly with energy density with higher densities having larger grains and enhanced post solidification diffusion. Energy density had minimal impact on the residuals stresses within the parameters to produce dense material.}, journal={Additive Manufacturing}, publisher={Elsevier BV}, author={Watkins, Thomas R. and Unocic, Kinga A. and Peralta, Alonso and Megahed, Mustafa and Bunn, Jeffrey R. and Fancher, Chris M. and D'Elia, Christopher R. and Hill, Michael R. and Neumann, James F.}, year={2021}, month={Nov}, pages={102334} }
 @article{cordon_zhang_purdy_wegener_unocic_allard_zhou_assary_miller_krause_et al._2021, title={Selective Butene Formation in Direct Ethanol-to-C<sub>3+</sub>-Olefin Valorization over Zn–Y/Beta and Single-Atom Alloy Composite Catalysts Using In Situ-Generated Hydrogen}, volume={11}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.1c01136}, DOI={10.1021/acscatal.1c01136}, abstractNote={The selective production of C3+ olefins from renewable feedstocks, especially via C1 and C2 platform chemicals, is a critical challenge for obtaining economically viable low-carbon middle-distillate transportation fuels (i.e., jet and diesel). Here, we report a multifunctional catalyst system composed of Zn–Y/Beta and "single-atom" alloy (SAA) Pt–Cu/Al2O3, which selectively catalyzes ethanol-to-olefin (C3+, ETO) valorization in the absence of cofed hydrogen, forming butenes as the primary olefin products. Beta zeolites containing predominately isolated Zn and Y metal sites catalyze ethanol upgrading steps (588 K, 3.1 kPa ethanol, ambient pressure) regardless of cofed hydrogen partial pressure (0–98.3 kPa H2), forming butadiene as the primary product (60% selectivity at an 87% conversion). The Zn–Y/Beta catalyst possesses site-isolated Zn and Y Lewis acid sites (at ∼7 wt % Y) and Brønsted acidic Y sites, the latter of which have been previously uncharacterized. A secondary bed of SAA Pt–Cu/Al2O3 selectively hydrogenates butadiene to butene isomers at a consistent reaction temperature using hydrogen generated in situ from ethanol to butadiene (ETB) conversion. This unique hydrogenation reactivity at near-stoichiometric hydrogen and butadiene partial pressures is not observed over monometallic Pt or Cu catalysts, highlighting these operating conditions as a critical SAA catalyst application area for conjugated diene selective hydrogenation at high reaction temperatures (>573 K) and low H2/diene ratios (e.g., 1:1). Single-bed steady-state selective hydrogenation rates, associated apparent hydrogen and butadiene reaction orders, and density functional theory (DFT) calculations of the Horiuti–Polanyi reaction mechanisms indicate that the unique butadiene selective hydrogenation reactivity over SAA Pt–Cu/Al2O3 reflects lower hydrogen scission barriers relative to monometallic Cu surfaces and limited butene binding energies relative to monometallic Pt surfaces. DFT calculations further indicate the preferential desorption of butene isomers over SAA Pt–Cu(111) and Cu(111) surfaces, while Pt(111) surfaces favor subsequent butene hydrogenation reactions to form butane over butene desorption events. Under operating conditions without hydrogen cofeeding, this combination of Zn–Y/Beta and SAA Pt–Cu catalysts can selectively form butenes (65% butenes, 78% C3+ selectivity at 94% conversion) and avoid butane formation using only in situ-generated hydrogen, avoiding costly hydrogen cofeeding requirements that hinder many renewable energy processes.}, number={12}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Cordon, Michael J. and Zhang, Junyan and Purdy, Stephen C. and Wegener, Evan C. and Unocic, Kinga A. and Allard, Lawrence F. and Zhou, Mingxia and Assary, Rajeev S. and Miller, Jeffrey T. and Krause, Theodore R. and et al.}, year={2021}, month={Jun}, pages={7193–7209} }
 @article{lardinois_bates_lippie_russell_miller_meyer_unocic_prikhodko_wei_lambert_et al._2021, title={Structural Interconversion between Agglomerated Palladium Domains and Mononuclear Pd(II) Cations in Chabazite Zeolites}, volume={33}, ISSN={0897-4756 1520-5002}, url={http://dx.doi.org/10.1021/acs.chemmater.0c04465}, DOI={10.1021/acs.chemmater.0c04465}, abstractNote={Palladium-exchanged zeolites are candidate materials for passive NOx adsorption in automotive exhaust aftertreatment, where mononuclear Pd cations behave as precursors to the purported NOx adsorption sites. Yet, the structures of zeolite lattice binding sites capable of stabilizing mononuclear Pd2+ ions, and the mechanisms that interconvert agglomerated PdO and Pd domains into mononuclear Pd2+ ions during Pd redispersion treatments, remain incompletely understood. Here, we use a suite of spectroscopic methods and quantitative site titration techniques to characterize mononuclear and agglomerated Pd species on zeolites with varying material properties and treatment history. Aqueous-phase methods to introduce Pd onto NH4-form zeolites initially form mononuclear [Pd(NH3)4]2+ complexes, but subsequent thermal treatments (573–723 K; air) lead to in situ formation of H2 that first reduces Pd2+ to metallic Pd domains, which are then oxidized by air to PdO domains. Progressive treatment of Pd-zeolites in air to higher temperatures (723–1023 K) converts larger fractions of agglomerated PdO to mononuclear Pd2+, as quantified by H2 temperature programmed reduction, because higher temperature treatments facilitate Pd redispersion toward deeper locations within chabazite (CHA) crystallites, which is corroborated by complementary titrimetric and spectroscopic data. Pd-CHA zeolites synthesized with similar bulk Pd and framework Al content, but varying framework Al arrangement, provide evidence that six-membered rings (6-MR) hosting paired Al sites (Al–O–(Si–O)x–Al, x = 1, 2) stabilize Pd2+ ions and that otherwise isolated Al sites can stabilize [PdOH]+ species, identifiable by an IR OH stretch at 3660 cm–1. These findings clarify the underlying chemical processes and gas environments that cause Pd agglomeration in zeolites and their subsequent redispersion to mononuclear Pd2+ ions, which prefer binding at 6-MR paired Al sites in CHA, and indicate that higher temperature air treatments lead to more uniform Pd spatial distributions throughout zeolite crystallites.}, number={5}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Lardinois, Trevor M. and Bates, Jason S. and Lippie, Harrison H. and Russell, Christopher K. and Miller, Jeffrey T. and Meyer, Harry M., III and Unocic, Kinga A. and Prikhodko, Vitaly and Wei, Xinyi and Lambert, Christine K. and et al.}, year={2021}, month={Feb}, pages={1698–1713} }
 @article{huq_hafenstine_huo_nguyen_tifft_conklin_stück_stunkel_yang_heyne_et al._2021, title={Toward net-zero sustainable aviation fuel with wet waste–derived volatile fatty acids}, volume={118}, ISSN={0027-8424 1091-6490}, url={http://dx.doi.org/10.1073/pnas.2023008118}, DOI={10.1073/pnas.2023008118}, abstractNote={Significance To meet the growing demand for sustainable aviation fuels (SAF), conversion pathways are needed that leverage wet waste carbon and meet jet fuel property specifications. Here, we demonstrate SAF production from food waste–derived volatile fatty acids (VFA) by targeting normal paraffins for a near-term path to market and branched isoparaffins to increase the renewable content long term. Combining these distinct paraffin structures was shown to synergistically improve VFA-SAF flash point and viscosity to increase the renewable blend limit to 70%. Life cycle analysis shows the dramatic impact on the carbon footprint if food waste is diverted from landfills to produce VFA-SAF, highlighting the potential to meet jet fuel safety, operability, and environmental goals.}, number={13}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Huq, Nabila A. and Hafenstine, Glenn R. and Huo, Xiangchen and Nguyen, Hannah and Tifft, Stephen M. and Conklin, Davis R. and Stück, Daniela and Stunkel, Jim and Yang, Zhibin and Heyne, Joshua S. and et al.}, year={2021}, month={Mar} }
 @article{adhikari_zhang_guo_unocic_tao_li_2020, title={A hybrid pathway to biojet fuel via 2,3-butanediol}, url={https://doi.org/10.1039/D0SE00480D}, DOI={10.1039/D0SE00480D}, abstractNote={A new hybrid pathway to biojet fuel <italic>via</italic> biomass-derived 2,3-butanediol has been demonstrated with high carbon recovery (74–82% of the theoretical maximum efficiency).}, journal={Sustainable Energy & Fuels}, publisher={Royal Society of Chemistry (RSC)}, author={Adhikari, Shiba P. and Zhang, Junyan and Guo, Qianying and Unocic, Kinga A. and Tao, Ling and Li, Zhenglong}, year={2020} }
 @article{to_wilke_nelson_nash_bartling_wegener_unocic_habas_foust_ruddy_2020, title={Dehydrogenative Coupling of Methanol for the Gas-Phase, One-Step Synthesis of Dimethoxymethane over Supported Copper Catalysts}, volume={8}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.0c03606}, DOI={10.1021/acssuschemeng.0c03606}, abstractNote={Oxymethylene dimethyl ethers (OMEs), CH3-(OCH2)n-OCH3, n = 1–5, possess attractive low-soot diesel fuel properties. Methanol is a key precursor in the production of OMEs, providing an opportunity to incorporate renewable carbon sources via gasification and methanol synthesis. The costly production of anhydrous formaldehyde in the typical process limits this option. In contrast, the direct production of OMEs via a dehydrogenative coupling (DHC) reaction, where formaldehyde is produced and consumed in a single reactor, may address this limitation. We report the gas-phase DHC reaction of methanol to dimethoxymethane (DMM), the simplest OME, with n = 1, over bifunctional metal–acid catalysts based on Cu. A Cu-zirconia-alumina (Cu/ZrAlO) catalyst achieved 40% of the DMM equilibrium-limited yield under remarkably mild conditions (200 °C, 1.7 atm). The performance of the Cu/ZrAlO catalyst was attributed to metallic Cu nanoparticles that enable dehydrogenation and a distribution of acid strengths on the ZrAlO support, which reduced the selectivity to dimethyl ether compared to a that obtained with a Cu/Al2O3 catalyst. The DMM formation rate of 6.1 h–1 compares favorably against well-studied oxidative DHC approaches over non-noble, mixed-metal oxide catalysts. The results reported here set the foundation for further development of the DHC route to OME production, rather than oxidative approaches.}, number={32}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={To, Anh The and Wilke, Trenton J. and Nelson, Eric and Nash, Connor P. and Bartling, Andrew and Wegener, Evan C. and Unocic, Kinga A. and Habas, Susan E. and Foust, Thomas D. and Ruddy, Daniel A.}, year={2020}, month={Aug}, pages={12151–12160} }
 @article{guo_kirka_unocic_2020, title={In Situ Transmission Electron Microscopy Study on the Deformation Responses of Additively Manufactured Multiphase Ni-based Superalloy}, volume={26}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927620019571}, DOI={10.1017/s1431927620019571}, abstractNote={Journal Article In Situ Transmission Electron Microscopy Study on the Deformation Responses of Additively Manufactured Multiphase Ni-based Superalloy Get access Qianying Guo, Qianying Guo Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States Search for other works by this author on: Oxford Academic Google Scholar Michael M Kirka, Michael M Kirka Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States Search for other works by this author on: Oxford Academic Google Scholar Kinga A Unocic Kinga A Unocic Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 26, Issue S2, 1 August 2020, Pages 1844–1846, https://doi.org/10.1017/S1431927620019571 Published: 01 August 2020}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Guo, Qianying and Kirka, Michael M. and Unocic, Kinga A.}, year={2020}, month={Jul}, pages={1844–1846} }
 @article{guo_kirka_lin_shin_peng_unocic_2020, title={In situ transmission electron microscopy deformation and mechanical responses of additively manufactured Ni-based superalloy}, volume={186}, url={https://doi.org/10.1016/j.scriptamat.2020.04.012}, DOI={10.1016/j.scriptamat.2020.04.012}, abstractNote={In situ nanodeformation by sharp indenter tip on nanopillars of various sizes was applied on an additively manufactured Ni-based alloy containing equiaxed grains and nano-features for the first time. In situ microscopy compression results showed more homogeneous deformation of the smaller nanopillars (compression mode) than the larger ones (indentation mode) due to their length and the contact area between the nanopillar and the indenter tip established during in situ deformation tests. Finite element modeling indicated a higher average stress level in smaller nanopillars. The local mechanical response of additively manufactured 718 was similar to a wrought 718 alloy.}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Guo, Qianying and Kirka, Michael and Lin, Lianshan and Shin, Dongwon and Peng, Jian and Unocic, Kinga A.}, year={2020}, month={Sep}, pages={57–62} }
 @article{mao_maxim_massey_unocic_edmondson_field_2020, title={In-situ Micromechanical Testing of Neutron Irradiated FeCrAl Alloys}, volume={26}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927620015391}, DOI={10.1017/s1431927620015391}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Mao, Keyou and Maxim, Gussev and Massey, Caleb and Unocic, Kinga and Edmondson, Philip and Field, Kevin}, year={2020}, month={Jul}, pages={646–647} }
 @article{unocic_walden_marthe_datye_bigelow_allard_2020, title={Introducing and Controlling Water Vapor in Closed-Cell <i>In Situ</i> Electron Microscopy Gas Reactions}, volume={26}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927620000185}, DOI={10.1017/s1431927620000185}, abstractNote={Protocols for conducting in situ transmission electron microscopy (TEM) reactions using an environmental TEM with dry gases have been well established. However, many important reactions that are relevant to catalysis or high-temperature oxidation occur at atmospheric pressure and are influenced by the presence of water vapor. These experiments necessitate using a closed-cell gas reaction TEM holder. We have developed protocols for introducing and controlling water vapor concentrations in experimental gases from 2% at a full atmosphere to 100% at ~17 Torr, while measuring the gas composition using a residual gas analyzer (RGA) on the return side of the in situ gas reactor holder. Initially, as a model system, cube-shaped MgO crystals were used to help develop the protocols for handling the water vapor injection process and confirming that we could successfully inject water vapor into the gas cell. The interaction of water vapor with MgO triggered surface morphological and chemical changes as a result of the formation of Mg(OH)2, later validated with mass spectra obtained with our RGA system with and without water vapor. Integrating an RGA with an in situ scanning/TEM closed-cell gas reaction system can thus provide critical measurements correlating gas composition with dynamic surface restructuring of materials during reactions.}, number={2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A. and Walden, Franklin S. and Marthe, Nelson L. and Datye, Abhaya K. and Bigelow, Wilbur C. and Allard, Lawrence F.}, year={2020}, month={Mar}, pages={229–239} }
 @article{unocic_chen_tortorelli_2020, title={Microstructural Evaluation of Welded Nickel-Based Superalloy Inconel 740H After Creep Testing}, volume={72}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/s11837-020-04119-2}, DOI={10.1007/s11837-020-04119-2}, number={5}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Chen, Xiang and Tortorelli, Peter F.}, year={2020}, month={Mar}, pages={1811–1821} }
 @article{guo_meyer_ievlev_starace_mukarakate_habas_veith_unocic_2020, title={Multi-scale Characterization Study Enabling Deactivation Mechanism in Formed Zeolite Catalyst}, volume={26}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927620017535}, DOI={10.1017/s1431927620017535}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Guo, Qianying and Meyer, Harry M., III and Ievlev, Anton and Starace, Anne and Mukarakate, Calvin and Habas, Susan E. and Veith, Gabriel M. and Unocic, Kinga A.}, year={2020}, month={Jul}, pages={1270–1271} }
 @article{unocic_griffin_yung_wegener_krause_wang_schaidle_allard_meyer_2020, title={Operando</i> S/TEM Reactions of Pt/TiO<sub>2</sub> Catalysts for Catalytic Fast Pyrolysis}, volume={26}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927620019005}, DOI={10.1017/s1431927620019005}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga and Griffin, Michael and Yung, Matthew and Wegener, Evan and Krause, Theodore and Wang, Huamin and Schaidle, Joshua and Allard, Lawrence and Meyer, Harry}, year={2020}, month={Jul}, pages={1696–1697} }
 @article{hafenstine_huq_conklin_wiatrowski_huo_guo_unocic_vardon_2020, title={Single-phase catalysis for reductive etherification of diesel bioblendstocks}, url={https://doi.org/10.1039/D0GC00939C}, DOI={10.1039/D0GC00939C}, abstractNote={We developed a single-phase Pd/NbOPO<sub>4</sub> catalyst for reductive etherification that displays high catalytic activity, product selectivity, and regeneration stability.}, journal={Green Chemistry}, publisher={Royal Society of Chemistry (RSC)}, author={Hafenstine, Glenn R. and Huq, Nabila A. and Conklin, Davis R. and Wiatrowski, Matthew R. and Huo, Xiangchen and Guo, Qianying and Unocic, Kinga A. and Vardon, Derek R.}, year={2020} }
 @article{boebinger_yarema_yarema_unocic_unocic_wood_mcdowell_2020, title={Spontaneous and reversible hollowing of alloy anode nanocrystals for stable battery cycling}, volume={15}, ISSN={1748-3387 1748-3395}, url={http://dx.doi.org/10.1038/s41565-020-0690-9}, DOI={10.1038/s41565-020-0690-9}, abstractNote={High-capacity alloy anode materials for Li-ion batteries have long been held back by limited cyclability caused by the large volume changes during lithium insertion and removal. Hollow and yolk-shell nanostructures have been used to increase the cycling stability by providing an inner void space to accommodate volume changes and a mechanically and dimensionally stable outer surface. These materials, however, require complex synthesis procedures. Here, using in situ transmission electron microscopy, we show that sufficiently small antimony nanocrystals spontaneously form uniform voids on the removal of lithium, which are then reversibly filled and vacated during cycling. This behaviour is found to arise from a resilient native oxide layer that allows for an initial expansion during lithiation but mechanically prevents shrinkage as antimony forms voids during delithiation. We developed a chemomechanical model that explains these observations, and we demonstrate that this behaviour is size dependent. Thus, antimony naturally evolves to form optimal nanostructures for alloy anodes, as we show through electrochemical experiments in a half-cell configuration in which 15-nm antimony nanocrystals have a consistently higher Coulombic efficiency than larger nanoparticles. Sufficiently small antimony nanoparticles form uniform voids that are reversibly filled and vacated during cycling.}, number={6}, journal={Nature Nanotechnology}, publisher={Springer Science and Business Media LLC}, author={Boebinger, Matthew G. and Yarema, Olesya and Yarema, Maksym and Unocic, Kinga A. and Unocic, Raymond R. and Wood, Vanessa and McDowell, Matthew T.}, year={2020}, month={Jun}, pages={475–481} }
 @article{kane_garcia_uwanyuze_lance_unocic_sampath_pint_2021, title={Steam oxidation of ytterbium disilicate environmental barrier coatings with and without a silicon bond coat}, volume={104}, ISSN={0002-7820 1551-2916}, url={http://dx.doi.org/10.1111/jace.17650}, DOI={10.1111/jace.17650}, abstractNote={Abstract The current generation of multilayer Si/Yb 2 Si 2 O 7 environmental barrier coatings (EBCs) are temperature limited by the melting point of Si, 1414°C. To investigate higher temperature EBCs, the cyclic steam oxidation of EBCs comprised of a single layer of ytterbium disilicate (YbDS) was compared to multilayered Si/YbDS EBCs, both deposited on SiC substrates using atmospheric plasma spray. After 500 1‐h cycles at 1300°C in 90 vol%H 2 O‐10 vol%air with a gas velocity of 1.5 cm/s, both multilayer Si/YbDS and single layer YbDS grew thinner silica scales than bare SiC, with the single layer YbDS forming the thinnest scale. Both coatings remained fully adherent and showed no signs of delamination. Silica scales formed on the single layer coating were significantly more homogeneous and possessed a markedly lower degree of cracking compared to the multilayered EBC. The single layer EBC also was exposed at 1425°C in steam with a gas velocity of 14 cm/s in an alumina reaction tube. The EBC reduced specimen mass loss compared to bare SiC but formed an extensive 2nd phase aluminosilicate reaction product. A similar reaction product was observed to form on some regions of the bare SiC specimen and appeared to partially inhibit silica volatilization. The 1425°C steam exposures were repeated with a SiC reaction tube and no 2nd phase reaction product was observed to form on the single layer EBC or bare SiC.}, number={5}, journal={Journal of the American Ceramic Society}, publisher={Wiley}, author={Kane, Ken A. and Garcia, Eugenio and Uwanyuze, Sharon and Lance, Michael and Unocic, Kinga A. and Sampath, Sanjay and Pint, Bruce A.}, year={2021}, month={Jan}, pages={2285–2300} }
 @book{pint_wang_hawkins_unocic_2020, title={Technical Qualification of New Materials for High Efficiency Coal-Fired Boilers and Other Advanced FE Concepts: Haynes® 282® ASME Boiler and Pressure Vessel Code Case}, url={https://doi.org/10.2172/1649169}, DOI={10.2172/1649169}, institution={Office of Scientific and Technical Information (OSTI)}, author={Pint, Bruce and Wang, Hong and Hawkins, Charles and Unocic, Kinga}, year={2020}, month={Jun} }
 @article{massey_edmondson_unocic_yang_dryepondt_kini_gault_terrani_zinkle_2020, title={The effect of Zr on precipitation in oxide dispersion strengthened FeCrAl alloys}, volume={533}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2020.152105}, DOI={10.1016/j.jnucmat.2020.152105}, abstractNote={Oxide dispersion strengthened (ODS) FeCrAl alloys are promising candidate materials for advanced nuclear reactor applications requiring high-temperature strength, corrosion resistance, and irradiation tolerance. As these alloys have increased in compositional complexity through attempts to use highly reactive elements such as Zr to refine particle sizes and optimize nanoprecipitate dispersion characteristics, much debate has ensued as to the effects of these alloying element additions on alloy properties. In an attempt to reconcile differences in nanoprecipitate distributions reported in the literature over the past decade, a detailed investigation of a recently developed ODS FeCrAl alloy with nominal composition Fe–10Cr-6.1Al-0.3Zr+0.3Y2O3 is presented using a combination of atom probe tomography (APT), scanning/transmission electron microscopy (S/TEM), and computational thermodynamics modeling. It is illustrated that based on the amount of Zr available in the lattice, Zr competes with Al and Cr to form carbides and nitrides as opposed to oxygen-rich precipitates. This alloy system has a high number density (>1023 m−3) of ∼2–4 nm diameter (Y,Al,O)-rich nanoprecipitates, but it is shown that due to the compositional spread and unknown partitioning of Al between the matrix and precipitates, significant challenges still exist for quantifying the exact compositions of these precipitates using APT. However, the noted compositional spread is supported by identified complex oxides yttrium aluminum monoclinic (YAM) and yttrium aluminum garnet (YAG) using S/TEM. As a result of these findings, researchers developing ODS FeCrAl with reactive element additions must pay careful attention to C and N impurities when optimizing reactive element additions.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Massey, Caleb P. and Edmondson, Philip D. and Unocic, Kinga A. and Yang, Ying and Dryepondt, Sebastien N. and Kini, Anoop and Gault, Baptiste and Terrani, Kurt A. and Zinkle, Steven J.}, year={2020}, month={May}, pages={152105} }
 @article{mudanyi_cramer_elliott_unocic_guo_kumar_2021, title={W-ZrC composites prepared by reactive melt infiltration of Zr2Cu alloy into binder jet 3D printed WC preforms}, volume={94}, ISSN={0263-4368}, url={http://dx.doi.org/10.1016/j.ijrmhm.2020.105411}, DOI={10.1016/j.ijrmhm.2020.105411}, abstractNote={W-ZrC composites were successfully prepared by reactive melt infiltration (RMI) of stoichiometric and excess amounts of Zr2Cu into sintered and un-sintered WC preforms made from binder jet 3D printing. The focus of this work was to study the conversion of reactant powders and liquid infiltrant with varying preform density and infiltrant amount by controlling the processing time to reach high conversion yield while understanding the phase composition, microstructure, and hardness. To investigate the effect of time, the reactive melt infiltration was conducted at 1400 °C for 2, 4 and 8 h in a furnace with 96% Ar - 4% H2 gas atmosphere. The increase in reaction time from 2 to 8 h increased the W and W2C phase contents and decreased the ZrC phase content when using sintered WC preforms. Samples prepared from un-sintered WC preforms exhibited improved reactive melt infiltration compared to sintered samples, and there was no detectable W2C phase and nearly full consumption of WC. Similar to sintered WC samples, the content of W and ZrC phases increased with the increase in time from 2 to 8 h. The interfaces and phases at reaction interfaces were investigated using electron diffraction analysis and S/TEM-EDS to understand material stability; the phases were identified and consistent with XRD analysis. Additionally, there was no Cu present at the interfaces. Increasing the amount of infiltrant led to better reactive melt infiltration. In general, the hardness increased with reaction time and the highest Vickers hardness was found in the W-ZrC sample formed from sintered WC reacted with excess Zr2Cu. This research addresses the critical comparison of sintering and RMI time and shows that by using un-sintered samples for 8 h we are able to achieve W-ZrC composites with fewer undesired phases.}, journal={International Journal of Refractory Metals and Hard Materials}, publisher={Elsevier BV}, author={Mudanyi, Rina K. and Cramer, Corson L. and Elliott, Amy M. and Unocic, Kinga A. and Guo, Qianying and Kumar, Dhananjay}, year={2021}, month={Jan}, pages={105411} }
 @article{jun_unocic_lance_meyer_pint_2020, title={Compatibility of FeCrAlMo with flowing PbLi at 500°-650 °C}, volume={528}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2019.151847}, DOI={10.1016/j.jnucmat.2019.151847}, abstractNote={To explore the upper temperature limit of a fusion blanket utilizing eutectic Pb-17at.%Li for tritium breeding, a series of three mono-metallic thermal convection loops have been fabricated from alloy APMT (Fe–21Cr–5Al–3Mo) and operated with commercial PbLi and increasing peak temperatures of 550°, 600° and 650 °C, flow rates of 0.4–0.7 cm/s and temperature gradients of 85–115 °C. Chains of APMT specimens including 25 mm long tensile specimens were hung in the hot and cold legs of the loops to evaluate post-exposure room temperature tensile properties after 1000 h exposures in each experiment. For specimens exposed to flowing PbLi above 500 °C, only minor changes in tensile properties were observed after exposure. Most APMT specimens were pre-oxidized to form alumina prior to exposure and exhibited small mass losses as the alumina was partially transformed to α-LiAlO2 that tended to spall after exposure. Specimens without pre-oxidation exhibited higher mass losses and formed γ-LiAlO2 but with less spallation. While promising for increasing blanket temperatures, the small mass losses suggest that the surface oxide is not completely stable. However, even at the highest temperatures, there was no indication of classic dissolution/precipitation behavior suggesting that higher temperature compatibility may be possible.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Jun, Jiheon and Unocic, Kinga A. and Lance, Michael J. and Meyer, Harry M., III and Pint, Bruce A.}, year={2020}, month={Jan}, pages={151847} }
 @article{ghimire_zhang_unocic_guo_jiang_jaroniec_2019, title={Development of nickel-incorporated MCM-41–carbon composites and their application in nitrophenol reduction}, volume={7}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/c9ta02387a}, DOI={10.1039/c9ta02387a}, abstractNote={Ni–MCM-41–carbon composites were obtained by the soft-templating synthesis of MCM-41 with addition of resorcinol, formaldehyde and nickel nitrate.}, number={16}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={Ghimire, Pramila P. and Zhang, Liping and Unocic, Kinga A. and Guo, Qianying and Jiang, Baojiang and Jaroniec, Mietek}, year={2019}, pages={9618–9628} }
 @inproceedings{pint_unocic_keiser_2019, title={Effect of impurities on supercritical CO2 compatibility}, booktitle={3rd European supercritical CO2 Conference}, author={Pint, B.A. and Unocic, K.A. and Keiser, J.}, year={2019}, month={Sep} }
 @article{settle_cleveland_farberow_conklin_huo_dameron_tracy_sarkar_kautz_devaraj_et al._2019, title={Enhanced Catalyst Durability for Bio-Based Adipic Acid Production by Atomic Layer Deposition}, volume={3}, ISSN={2542-4351}, url={http://dx.doi.org/10.1016/j.joule.2019.06.022}, DOI={10.1016/j.joule.2019.06.022}, abstractNote={Atomic layer deposition (ALD) improves the durability of metal catalysts using nanoscale metal oxide coatings. However, targeted coating strategies and economic models are lacking for process-specific deactivation challenges that account for implications at scale. Herein, we apply Al2O3 ALD to Pd/TiO2 to increase durability during hydrogenation of muconic acid, a bio-based platform chemical, to adipic acid. Initial coating development and characterization are performed on the milligram scale using stop-flow ALD. Subsequently, ALD coating scale is increased by 3 orders of magnitude using fluidized bed ALD. Activity, leaching resistance, and thermal stability are evaluated at each synthesis scale. ALD-coated catalysts retain up to 2-fold greater muconic acid hydrogenation activity and undergo significantly less physical restructuring than uncoated Pd/TiO2 after high-temperature treatments, while reducing Pd leaching by over 4-fold. Techno-economic analysis for an adipic acid biorefinery supports increased ALD material costs through catalyst lifetime extension, underscoring the potential viability of this technology.}, number={9}, journal={Joule}, publisher={Elsevier BV}, author={Settle, Amy E. and Cleveland, Nicholas S. and Farberow, Carrie A. and Conklin, Davis R. and Huo, Xiangchen and Dameron, Arrelaine A. and Tracy, Ryon W. and Sarkar, Reuben and Kautz, Elizabeth J. and Devaraj, Arun and et al.}, year={2019}, month={Sep}, pages={2219–2240} }
 @article{unocic_kirka_cakmak_greeley_okello_dryepondt_2020, title={Evaluation of additive electron beam melting of haynes 282 alloy}, volume={772}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/j.msea.2019.138607}, DOI={10.1016/j.msea.2019.138607}, abstractNote={The electron beam melting (EBM) process is an attractive additive manufacturing technology that can be applied to a number of different materials. However, fabrication of each material requires tweaking and identifying optimal processing parameters. In this study, process parameters were successively varied to identify a processing regime to fabricate the nickel-base (Ni-base) superalloy Haynes 282. Key parameters to minimize porosity and mitigate the potential for cracking were beam velocity, beam current, hatch spacing, line order, and beam focus. Overall, the EBM process window produced a combination of promising microstructure and 99.5% dense material with no observable cracking. Electron backscatter diffraction revealed a crystallographic texture along the [001] direction of the cube orientation aligned with the build direction. Within the grain interiors of the as-fabricated material were observed uniformly distributed γ′ precipitates with a size distribution ranging from ~80 nm spherical to ~190 nm cuboidal particles with an average particle size of ~128 nm. Grain boundary carbides were observed in two morphologies: blocky and thin film–like. Hardness and tensile testing of the as-fabricated EBM material indicated a 10% higher hardness and slightly lower tensile strength compared with the as-annealed wrought form of the Haynes 282 alloy. The EBM alloy exhibited pronounced ductility except at T > 600 °C perpendicular to the build direction. Annealing based on standard wrought heat treatments showed that γ′ precipitates measuring 20–30 nm in average size can be achieved to improve the alloy's high-temperature performance.}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Unocic, K.A. and Kirka, M.M. and Cakmak, E. and Greeley, D. and Okello, A.O. and Dryepondt, S.}, year={2020}, month={Jan}, pages={138607} }
 @article{thind_kavadiya_kouhnavard_wheelus_cho_lin_kacica_mulmudi_unocic_borisevich_et al._2019, title={KBaTeBiO<sub>6</sub>: A Lead-Free, Inorganic Double-Perovskite Semiconductor for Photovoltaic Applications}, volume={31}, ISSN={0897-4756 1520-5002}, url={http://dx.doi.org/10.1021/acs.chemmater.9b01025}, DOI={10.1021/acs.chemmater.9b01025}, abstractNote={Solar cells made up of lead-halide perovskites have shown a remarkable increase in power conversion efficiency; however, they are plagued with instability issues that, combined with the toxicity of lead, have led to a search for new semiconductors made up of heavy and nontoxic metals such as bismuth. Here, we report on a new, inorganic, double perovskite oxide semiconductor: KBaTeBiO6, which has an experimental indirect band gap of 1.88 eV and shows excellent stability. We combined data analytics and high throughput density functional theory calculations to search through thousands of hypothetical inorganic double perovskite oxides containing bismuth and predict KBaTeBiO6 as a potential photovoltaic material, which was subsequently synthesized using a wet-chemistry route. The calculated effective mass of the charge carriers for KBaTeBiO6 is comparable to the best performing Bi-halide double perovskites. Our work demonstrates the untapped potential of inorganic Bi-based double perovskite oxides—that offer the ability to change both the cation combination and their stoichiometry to achieve desired electronic properties—as exciting, benign, and stable alternatives to lead-halide perovskites for various semiconducting applications.}, number={13}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Thind, Arashdeep Singh and Kavadiya, Shalinee and Kouhnavard, Mojgan and Wheelus, Robin and Cho, Sung Beom and Lin, Liang-Yi and Kacica, Clayton and Mulmudi, Hemant Kumar and Unocic, Kinga A. and Borisevich, Albina Y. and et al.}, year={2019}, month={Jun}, pages={4769–4778} }
 @book{jun_unocic_petrova_shipilov_carvalhaes_thakur_piburn_pint_2019, title={Methodologies for Evaluation of Corrosion Protection for Ductile Iron Pipe}, url={https://doi.org/10.2172/1528741}, DOI={10.2172/1528741}, abstractNote={made on pipe sliced lengthwise into quarter sections, and in re-assembled whole pipe sections. X-ray films of the quarter sections indicated probable areas of corrosion for each quarter section.}, author={Jun, Jiheon and Unocic, Kinga and Petrova, Margarita and Shipilov, Sergei and Carvalhaes, Thomaz and Thakur, Gautam Malviya and Piburn, Jesse and Pint, Bruce}, year={2019}, month={Jun} }
 @article{unocic_meyer_walden_marthe_bigelow_allard_2018, title={Controlling Water Vapor in Gas-Cell Microscopy Experiments}, volume={24}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927618001927}, DOI={10.1017/s1431927618001927}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, K. A. and Meyer, H. M. and Walden, F. S. and Marthe, N. L. and Bigelow, W. C. and Allard, L. F.}, year={2018}, month={Aug}, pages={286–287} }
 @article{dryepondt_unocic_hoelzer_massey_pint_2018, title={Development of low-Cr ODS FeCrAl alloys for accident-tolerant fuel cladding}, volume={501}, url={https://doi.org/10.1016/j.jnucmat.2017.12.035}, DOI={10.1016/j.jnucmat.2017.12.035}, abstractNote={Low-Cr oxide dispersion strengthened (ODS) FeCrAl alloys were developed as accident tolerant fuel cladding because of their excellent oxidation resistance at very high temperature, high strength and improved radiation tolerance. Fe-12Cr-5Al wt.% gas atomized powder was ball milled with Y2O3+FeO, Y2O3+ZrO2 or Y2O3+TiO2, and the resulting powders were extruded at 950 °C. The resulting fine grain structure, particularly for the Ti and Zr containing alloys, led to very high strength but limited ductility. Comparison with variants of commercial PM2000 (Fe-20Cr-5Al) highlighted the significant impact of the powder consolidation step on the alloy grain size and, therefore, on the alloy mechanical properties at T < 500 °C. These low-Cr compositions exhibited good oxidation resistance at 1400 °C in air and steam for 4 h but could not form a protective alumina scale at 1450 °C, similar to observations for fine grained PM2000 alloys. The effect of alloy grain size, Zr and Ti additions, and impurities on the alloy mechanical and oxidation behaviors are discussed.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Dryepondt, Sebastien and Unocic, Kinga A. and Hoelzer, David T. and Massey, Caleb P. and Pint, Bruce A.}, year={2018}, month={Apr}, pages={59–71} }
 @article{ariza_poplawsky_guo_unocic_ramirez_tschiptschin_babu_2018, title={Evaluation of Carbon Partitioning in New Generation of Quench and Partitioning (Q&P) Steels}, volume={49}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/s11661-018-4743-8}, DOI={10.1007/s11661-018-4743-8}, abstractNote={Quenching and partitioning (Q&P) and a novel combined process of hot straining (HS) and Q&P (HSQ&P) treatments have been applied to a TRIP-assisted steel in a Gleeble®3S50 thermomechanical simulator. The heat treatments involved intercritical annealing at 800 °C and a two-step Q&P heat treatment with a partitioning time of 100 seconds at 400 °C. The "optimum" quench temperature of 318 °C was selected according to the constrained carbon equilibrium (CCE) criterion. The effects of high-temperature deformation (isothermal and non-isothermal) on the carbon enrichment of austenite, carbide formation, and the strain-induced transformation to ferrite (SIT) mechanism were investigated. Carbon partitioning from supersaturated martensite into austenite and carbide precipitation were confirmed by means of atom probe tomography (APT) and scanning transmission electron microscopy (STEM). Austenite carbon enrichment was clearly observed in all specimens, and in the HSQ&P samples, it was significantly greater than in Q&P, suggesting an additional carbon partitioning to austenite from ferrite formed by the deformation-induced austenite-to-ferrite transformation (DIFT) phenomenon. By APT, the carbon accumulation at austenite/martensite interfaces was observed, with higher values for HSQ&P deformed isothermally (≈ 11 at. pct), when compared with non-isothermal HSQ&P (≈ 9.45 at. pct) and Q&P (≈ 7.6 at. pct). Moreover, a local Mn enrichment was observed in a ferrite/austenite interface, indicating ferrite growth under local equilibrium with negligible partitioning (LENP).}, number={10}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Ariza, Edwan Anderson and Poplawsky, Jonathan and Guo, Wei and Unocic, Kinga and Ramirez, Antonio J. and Tschiptschin, André P. and Babu, Sudarsanam Suresh}, year={2018}, month={Jun}, pages={4809–4823} }
 @article{barr_nathaniel_unocic_liu_zhang_wang_taheri_2018, title={Exploring radiation induced segregation mechanisms at grain boundaries in equiatomic CoCrFeNiMn high entropy alloy under heavy ion irradiation}, volume={156}, ISSN={1359-6462}, url={http://dx.doi.org/10.1016/j.scriptamat.2018.06.041}, DOI={10.1016/j.scriptamat.2018.06.041}, abstractNote={High entropy alloys have gained significant interest due to several unique properties including enhanced radiation resistance. In this work, radiation induced segregation, a key phenomenon observed in alloys under irradiation, is examined for the first time at high angle grain boundaries under Ni heavy ion irradiation in the CoCrFeNiMn alloy. Our experimental study indicates significant Mn depletion and Co and Ni enrichment at grain boundaries. The segregation is discussed in the context of a proposed vacancy dominated radiation induced segregation mechanism and compared to existing models in conventional single core component alloys including stainless steels.}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Barr, Christopher M. and Nathaniel, James E., II and Unocic, Kinga A. and Liu, Junpeng and Zhang, Yong and Wang, Yongqiang and Taheri, Mitra L.}, year={2018}, month={Nov}, pages={80–84} }
 @article{unocic_choi_ruddy_yang_kropf_miller_krause_habas_2018, title={In Situ S/TEM Reduction Reaction of Ni-Mo2C Catalyst for Biomass Conversion}, volume={24}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927618002106}, DOI={10.1017/s1431927618002106}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A. and Choi, Jae-Soon and Ruddy, Daniel A. and Yang, Ce and Kropf, Jeremy and Miller, Jeffrey and Krause, Theodore R. and Habas, Susan}, year={2018}, month={Aug}, pages={322–323} }
 @book{kirka_unocic_kruger_forsythe_2018, title={Process Development for Haynes® 282® Using Additive Manufacturing}, url={https://doi.org/10.2172/1435227}, DOI={10.2172/1435227}, abstractNote={ORNL, in collaboration with Haynes International successfully demonstrated the ability to process the nickel-base superalloy Haynes® 282® for additive manufacturing using electron beam melting (EBM). The EBM processed Haynes® 282® material was found to exhibit favorable microstructure and mechanical properties when compared to traditional wrought product.}, author={Kirka, Michael M. and Unocic, Kinga A. and Kruger, Keith and Forsythe, Alison}, year={2018}, month={Apr} }
 @article{foster_carver_dinwiddie_list_unocic_chaudhary_babu_2018, title={Process-Defect-Structure-Property Correlations During Laser Powder Bed Fusion of Alloy 718: Role of In Situ and Ex Situ Characterizations}, volume={49}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/s11661-018-4870-2}, DOI={10.1007/s11661-018-4870-2}, abstractNote={Components made by laser powder bed fusion (L-PBF) additive processes require extensive trial and error optimization to minimize defects and arrive at targeted microstructure and properties. In this work, in situ infrared thermography and ex situ surface roughness measurements were explored as methodologies to ensure Inconel® 718-part quality. For a given laser energy of 200 Watts, prismatic samples were produced with different exposure times (80 to 110 µs) and point spacings (80 to 110 µm). The infrared intensities from laser–material interaction zones were measured spatially and temporally. The conditions leading to higher IR intensity and lowest surface roughness values correlated well with less porosity and coarse solidification grain structure. The transition from highly columnar to misoriented growth is attributed to changes in thermal gradients and liquid–solid interface velocities. Hardness measurements and electron microscopy of the as-processed and post-processed heat-treated samples show complex transitions in microstructural states including the heavily dislocated FCC matrix, reduction of dislocation density, and copious precipitation, respectively. These results show that the geometry-process-structure-property correlations are dynamic, and they cascade depending on the transitions of phase states from powder to liquid to solid, as well as phase decompositions and deformations within the solid FCC phase. Validity of using analytical weld process models to describe the above phenomena is also highlighted.}, number={11}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Foster, S. J. and Carver, K. and Dinwiddie, R. B. and List, F., III and Unocic, K. A. and Chaudhary, A. and Babu, S. S.}, year={2018}, month={Aug}, pages={5775–5798} }
 @book{watkins_unocic_maziasz_bunn_fancher_peralta_sundarraj_neumann_2018, title={Residual stress determination of direct metal laser sintered (DMLS) inconel specimens and parts}, url={https://doi.org/10.2172/1415913}, DOI={10.2172/1415913}, abstractNote={Residual stress determinations and microstructural studies were performed on a series of Inconel 718Plus prisms built using Direct Metal Laser Sintering (DMLS) at Honeywell Aerospace (hereafter also referred to as Honeywell). The results are being used to validate and improve existing models at Honeywell, and ultimately will expedite the implementation of DMLS throughout various industrial sectors (automotive, biomedical, etc.).}, author={Watkins, Thomas and Unocic, Kinga and Maziasz, Philip and Bunn, Jeffrey and Fancher, Christopher and Peralta, Alonso and Sundarraj, Suresh and Neumann, James}, year={2018}, month={Jan} }
 @article{unocic_chen_shin_pint_marquis_2018, title={STEM and APT characterization of scale formation on a La,Hf,Ti-doped NiCrAl model alloy}, volume={109}, ISSN={0968-4328}, url={http://dx.doi.org/10.1016/j.micron.2018.01.011}, DOI={10.1016/j.micron.2018.01.011}, abstractNote={A thermally grown scale formed on a cast NiCrAl model alloy doped with lanthanum, hafnium, and titanium was examined after isothermal exposure at 1100 °C for 100 h in dry flowing O2 to understand the dopant segregation along scale grain boundaries. The complex scale formed on the alloy surface was composed of two types of substrates: phase-dependent, thin (<250 nm) outer layers and a columnar-grained ∼3.5 μm inner alumina layer. Two types of oxides formed between the inner and outer scale layers: small (3–15 nm) La2O3 and larger (≤50 nm) HfO2 oxide precipitates. Nonuniform distributions of the hafnium, lanthanum, and titanium dopants were observed along the inner scale grain boundaries, with hafnium dominating in most of the grain boundaries of α-Al2O3. The concentration of reactive elements (RE) seemed to strongly depend on the grain boundary structure. The level of titanium grain boundary segregation in the inner scale decreased toward the model alloy (substrate), confirming the fast outward diffusion of titanium. Hafnium was also observed at the metal–scale interface and in the γ′ (Ni3Al) phase of the alloy. High-resolution scanning transmission electron microscopy (STEM) confirmed the substitution of REs for aluminum atoms at the scale grain boundaries, consistent with both the semiconducting band structure and the site-blocking models. Both STEM and atom probe tomography allowed quantification of REs along the scale grain boundaries across the scale thickness. Analysis of the scale morphology after isothermal exposure in flowing oxygen revealed a myriad of new precipitate phases, RE segregation dependence on grain boundary type, and atomic arrangement along scale grain boundaries, which is expected to influence the scale growth rate, stability, and mechanical properties.}, journal={Micron}, publisher={Elsevier BV}, author={Unocic, Kinga A. and Chen, Yimeng and Shin, Dongwon and Pint, Bruce A. and Marquis, Emmanuelle A.}, year={2018}, month={Jun}, pages={41–52} }
 @article{unocic_shin_sang_cakmak_tortorelli_2019, title={Single-step aging treatment for a precipitation-strengthened Ni-based alloy and its influence on high-temperature mechanical behavior}, volume={162}, ISSN={1359-6462}, url={http://dx.doi.org/10.1016/j.scriptamat.2018.11.045}, DOI={10.1016/j.scriptamat.2018.11.045}, abstractNote={A simplified aging treatment yielded microstructural features in Ni-based alloy that produced strengthening behavior normally associated with more complex thermal processing. Specifically, a time series of 800 °C heat treatments was used to study the evolution of grain boundary carbides and γ' precipitates and the corresponding hardness, tensile strength, and creep resistance. These analyses and computational thermodynamic calculations revealed that a 4-hour aging treatment produced appropriately sized and uniformly distributed coherent γ' precipitates and the desired Cr-rich carbides like those formed during the conventional two-step heat treatment. Accordingly, the former heat treatment produced targeted typical strength levels for this alloy.}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Unocic, Kinga A. and Shin, Dongwon and Sang, Xiahan and Cakmak, Ercan and Tortorelli, Peter F.}, year={2019}, month={Mar}, pages={416–420} }
 @article{pint_unocic_2018, title={The Effect of CO2 Pressure on Chromia Scale Microstructure at 750°C}, volume={70}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/s11837-018-2963-4}, DOI={10.1007/s11837-018-2963-4}, number={8}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Pint, B. A. and Unocic, K. A.}, year={2018}, month={Jun}, pages={1511–1519} }
 @article{pint_unocic_brese_keiser_2017, title={Characterization of chromia scales formed in supercritical carbon dioxide}, volume={35}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.1080/09603409.2017.1389371}, DOI={10.1080/09603409.2017.1389371}, abstractNote={Initial experimental work at 700°–800 °C is in progress to develop a lifetime model for supercritical CO2 (sCO2) compatibility for a 30-year lifetime of a >700 °C concentrated solar power system. Nickel-based alloys 282, 740H and 625 and Fe-based alloy 25 are being evaluated in 500-h cycles at 1 and 300 bar, and 10-h cycles in 1 bar industrial grade CO2. The alloys showed similar low rates of oxidation in 1 and 300 bar CO2 in 500-h cycles at 750 °C. However, in 10-h cycles, alloy 25 showed accelerated attack at 700° and 750 °C. Transmission electron microscopy scale cross-sections on alloy 25 after 1000 h at 700 °C in sCO2 and in air only showed a small row of carbides beneath the scale in the former environment. Similar characterisation was performed on alloys 625 and 282 after sCO2 exposure at 750 °C.}, number={1-3}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Pint, B. A. and Unocic, K. A. and Brese, R. G. and Keiser, J. R.}, year={2017}, month={Oct}, pages={39–49} }
 @article{pawel_unocic_2017, title={Compatibility of an FeCrAl alloy with flowing Pb-Li in a thermal convection loop}, volume={492}, url={https://doi.org/10.1016/j.jnucmat.2017.04.048}, DOI={10.1016/j.jnucmat.2017.04.048}, abstractNote={A mono-metallic thermal convection loop (TCL) fabricated from alloy APMT (Fe21Cr5Al3Mo) tubing and filled with 0.025 m long tensile specimens of the same alloy was operated continuously for 1000 h with commercially pure Pb-17 at.%Li (Pb-Li) at a peak temperature of 550 ± 1.5 °C and a temperature gradient of ∼116 °C. The resulting Pb-Li flow rate was ∼0.0067 m/s. A 1050 °C pre-oxidation treatment (to form an external alumina scale) given to most specimens exposed within the TCL decreased total mass loss by a factor of 3–30 compared to adjacent specimens that were not pre-oxidized. However, all specimens exposed above 500 °C lost mass suggesting that the alumina scale was not entirely stable in flowing Pb-Li at these temperatures. Post-exposure room temperature tensile tests indicated that the mechanical properties of APMT were substantially influenced by extended exposures in the range of 435–490 °C, which caused an increase in yield strength (∼65%) and a corresponding decrease in ductility associated with α′ embrittlement. Specimens annealed in argon at the same temperature exhibited identical changes without exposure to Pb-Li. Scanning transmission electron microscopy revealed Cr-clusters within the microstructure in specimens exposed in the low temperature regions (<490 °C) of the TCL, indicating the formation of α′ consistent with the mechanism of α′ embrittlement.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Pawel, Steven J. and Unocic, Kinga A.}, year={2017}, month={Aug}, pages={41–51} }
 @article{unocic_yamamoto_pint_2017, title={Effect of Al and Cr Content on Air and Steam Oxidation of FeCrAl Alloys and Commercial APMT Alloy}, volume={87}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-017-9745-1}, DOI={10.1007/s11085-017-9745-1}, number={3-4}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Yamamoto, Yukinori and Pint, Bruce A.}, year={2017}, month={Mar}, pages={431–441} }
 @article{meyer_han_hijazi_bannister_unocic_parish_krstic_2017, title={Energy dependence of He-ion-induced tungsten nanofuzz formation at non-normal incidence angles}, volume={12}, ISSN={2352-1791}, url={http://dx.doi.org/10.1016/j.nme.2017.01.013}, DOI={10.1016/j.nme.2017.01.013}, abstractNote={We report measurements of He-ion-beam induced tungsten nanofuzz formation for normal and non-normal incidence angles in the energy range 218 eV–10 keV. At 218 eV, the fuzz tendrils are fine and grow randomly away from the interface in the direction of the surface normal. Above 480 eV, the fuzz tendrils become increasingly coarser, and their growth direction is in the direction of the incident beam. This change is attributed to the ion-induced displacement damage which becomes effective once the displacement damage threshold energy is exceeded, and produces additional near-surface trapping sites in those portions of the surface that are in direct line of sight of the incident beam which can nucleate He clusters and initiate bubble growth. Once the surface morphology roughens sufficiently for shadowing to occur, the subsequent fuzz growth occurs preferentially toward the incident ion beam. Molecular dynamics (MD) simulations were carried out to determine the displacement damage threshold energies in the near-surface region along the three major crystallographic directions. It was found that the tungsten bulk values are established within the first 2–4 atomic layers below the tungsten surface. SRIM simulations based on the MD energy thresholds indicate that vacancy damage production in the near-surface region quickly dominates over sputtering in near-surface lattice modification effects as the energy above the damage threshold increases.}, journal={Nuclear Materials and Energy}, publisher={Elsevier BV}, author={Meyer, F.W. and Han, L. and Hijazi, H. and Bannister, M.E. and Unocic, K.A. and Parish, C.M. and Krstic, P.S.}, year={2017}, month={Aug}, pages={366–371} }
 @article{bergholz_pint_unocic_vaßen_2017, title={Fabrication of Oxide Dispersion Strengthened Bond Coats with Low Al2O3 Content}, volume={26}, ISSN={1059-9630 1544-1016}, url={http://dx.doi.org/10.1007/s11666-017-0550-9}, DOI={10.1007/s11666-017-0550-9}, abstractNote={Nanoscale oxide dispersions have long been used to increase the oxidation and wear resistance of alloys used as bond coatings in thermal barrier coatings. Their manufacturing via mechanical alloying is often accompanied by difficulties regarding their particle size, homogeneous distribution of the oxide dispersions inside the powder, involving considerable costs, due to cold welding of the powder during milling. A significant improvement in this process can be achieved by the use of process control agent (PCA) to achieve the critical balance between cold welding and fracturing, thereby enhancing the process efficiency. In this investigation, the influence of the organic additive stearic acid on the manufacturing process of Al2O3-doped CoNiCrAlY powder was investigated. Powders were fabricated via mechanical alloying at different milling times and PCA concentrations. The results showed a decrease in particle size, without hindering the homogeneous incorporation of the oxide dispersions. Two powders manufactured with 0.5 and 1.0 wt.% PCA were deposited by high velocity oxygen fuel (HVOF) spraying. Results showed that a higher content of elongated particles in the powder with the higher PCA content led to increased surface roughness, porosity and decreased coating thickness, with areas without embedded oxide particles.}, number={5}, journal={Journal of Thermal Spray Technology}, publisher={Springer Science and Business Media LLC}, author={Bergholz, Jan and Pint, Bruce A. and Unocic, Kinga A. and Vaßen, Robert}, year={2017}, month={Mar}, pages={868–879} }
 @article{boll_unocic_pint_mårtensson_stiller_2017, title={Grain Boundary Chemistry and Transport Through Alumina Scales on NiAl Alloys}, volume={88}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-016-9697-x}, DOI={10.1007/s11085-016-9697-x}, abstractNote={It is widely accepted that the growth of protective α-Al2O3 scales on Ni-based alloys is governed by the inward diffusion of oxygen through the oxide grain boundaries (GB). However, there is also some outward diffusion of metal ions to the surface, but it is difficult to quantify. In this work we apply atomic force microscopy, scanning electron microscopy and transmission electron microscopy to investigate the outward flux of Al, which manifests as the growth of small ridges along the alumina GBs after the removal of the outermost oxide layer by mechanical polishing or focused ion beam techniques followed by additional oxidation. As a model alumina-former, NiAl with Hf and Zr additions was investigated. In comparison to Zr, Hf was found to reduce the outward Al diffusion. This outward diffusion was six orders of magnitude smaller than the O inward diffusion.}, number={3-4}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Boll, Torben and Unocic, Kinga A. and Pint, Bruce A. and Mårtensson, Anders and Stiller, Krystyna}, year={2017}, month={Jan}, pages={469–479} }
 @article{unocic_bergholz_huang_naumenko_pint_vaßen_quadakkers_2017, title={High-temperature behavior of oxide dispersion strengthening CoNiCrAlY}, volume={35}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.1080/09603409.2017.1389423}, DOI={10.1080/09603409.2017.1389423}, abstractNote={To fabricate oxide dispersion strengthened bond coatings, commercial Co–30wt-%Ni–20Cr–8Al–0•4Y powder was milled with 2% additions of Al2O3, Y2O3 or Y2O3 + HfO2. Low-pressure plasma sprayed, free-standing specimens were oxidised in air + 10%H2O at 1100 °C both isothermally (100 h) and in 500, 1−h cycles. Dry air cyclic testing conducted at both ORNL and FZJ showed remarkably similar results. In general, the water vapour addition caused more scale spallation. Two LPPS specimens without oxide additions were tested for comparison. The specimens with 2%Al2O3 addition exhibited the best behaviour as the powder already contained 0•4%Y. Additions of 2%Y2O3 and especially 1%Y2O3 + 1%HfO2 resulted in over-doping as evidenced by high mass gains and the formation of Y- and Hf-rich pegs. Scanning transmission electron microscopy of the isothermal specimens showed no Hf and/or Y segregation to the alumina scale grain boundaries in the over-doped specimens.}, number={1-3}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Unocic, K. A. and Bergholz, J. and Huang, T. and Naumenko, D. and Pint, B. A. and Vaßen, R. and Quadakkers, W. J.}, year={2017}, month={Nov}, pages={108–119} }
 @article{unocic_sacci_sang_unocic_veith_dudney_more_2017, title={In situ</i> Nanoscale Imaging and Spectroscopy of Energy Storage Materials}, volume={23}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927617010480}, DOI={10.1017/s1431927617010480}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Raymond R. and Sacci, Robert L. and Sang, Xiahan and Unocic, Kinga A. and Veith, Gabriel M. and Dudney, Nancy J. and More, Karren L.}, year={2017}, month={Jul}, pages={1964–1965} }
 @article{unocic_ruddy_krause_habas_2017, title={In situ</i> S/TEM Reduction Reaction of Calcined Cu/BEA-zeolite Catalyst}, volume={23}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927617005384}, DOI={10.1017/s1431927617005384}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A. and Ruddy, Daniel A. and Krause, Theodore R. and Habas, Susan}, year={2017}, month={Jul}, pages={944–945} }
 @article{boll_unocic_pint_stiller_2017, title={Interfaces in Oxides Formed on NiAlCr Doped with Y, Hf, Ti, and B}, volume={23}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927617000186}, DOI={10.1017/s1431927617000186}, abstractNote={Abstract This study applies atom probe tomography (APT) to analyze the oxide scales formed on model NiAlCr alloys doped with Hf, Y, Ti, and B. Due to its ability to measure small amounts of alloying elements in the oxide matrix and its ability to quantify segregation, t he technique offers a possibility for detailed studies of the dopant’s fate during high-temperature oxidation. Three model NiAlCr alloys with different additions of Hf, Y, Ti, and B were prepared and oxidized in O 2 at 1,100°C for 100 h. All specimens showed an outer region consisting of different spinel oxides with relatively small grains and the protective Al 2 O 3 -oxide layer below. APT analyses focused mainly on this protective oxide layer. In all the investigated samples segregation of both Hf and Y to the oxide grain boundaries was observed and quantified. Neither B nor Ti were observed in the alumina grains or at the analyzed interfaces. The processes of formation of oxide scales and segregation of the alloying elements are discussed. The experimental challenges of the oxide analyses by APT are also addressed.}, number={2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Boll, Torben and Unocic, Kinga A. and Pint, Bruce A. and Stiller, Krystyna}, year={2017}, month={Mar}, pages={396–403} }
 @article{allard_meyer_hensley_bigelow_unocic_2017, title={Model “Alloy” Specimens for MEMS-Based Closed-Cell Gas-Reactions}, volume={23}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927617005207}, DOI={10.1017/s1431927617005207}, abstractNote={Journal Article Model “Alloy” Specimens for MEMS-Based Closed-Cell Gas-Reactions Get access Lawrence F Allard, Lawrence F Allard Materials Science & Technology Div., Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Harry M Meyer, III, Harry M Meyer, III Materials Science & Technology Div., Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Dale K Hensley, Dale K Hensley Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Wilbur C Bigelow, Wilbur C Bigelow Department of Materials Science & Engineering, University of Michigan, Ann Arbor, MI, USA Search for other works by this author on: Oxford Academic Google Scholar Kinga A Unocic Kinga A Unocic Materials Science & Technology Div., Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 23, Issue S1, 1 July 2017, Pages 908–909, https://doi.org/10.1017/S1431927617005207 Published: 04 August 2017}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Allard, Lawrence F. and Meyer, Harry M., III and Hensley, Dale K. and Bigelow, Wilbur C. and Unocic, Kinga A.}, year={2017}, month={Jul}, pages={908–909} }
 @article{unocic_shin_unocic_allard_2017, title={NiAl Oxidation Reaction Processes Studied In Situ Using MEMS-Based Closed-Cell Gas Reaction Transmission Electron Microscopy}, volume={88}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-016-9676-2}, DOI={10.1007/s11085-016-9676-2}, number={3-4}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Shin, Dongwon and Unocic, Raymond R. and Allard, Lawrence F.}, year={2017}, month={Feb}, pages={495–508} }
 @article{vardon_settle_vorotnikov_menart_eaton_unocic_steirer_wood_cleveland_moyer_et al._2017, title={Ru-Sn/AC for the Aqueous-Phase Reduction of Succinic Acid to 1,4-Butanediol under Continuous Process Conditions}, volume={7}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.7b02015}, DOI={10.1021/acscatal.7b02015}, abstractNote={Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn, Pd-Re) catalysts. Batch reactor tests determined that a ∼1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that are colocated and surface-enriched with Sn. Postbatch reaction characterization confirmed stable Ru-Sn material properties; however, upon a transition to continuous conditions, significant Ru-Sn/AC deactivation occurred due to stainless steel leaching of Ni that resulted in Ru-Sn metal crystallite restructuring to form discrete Ni-Sn sites. Computational modeling confirmed favorable energetics for Ru-Sn segregation and Ni-Sn formation at submonolayer Sn incorporation. To address stainless steel leaching, reactor walls were treated with an inert silica coating by chemical vapor deposition. With leaching reduced, stable Ru-Sn/AC performance was observed that resulted in a molar yield of 71% BDO and 15% tetrahydrofuran for 96 h of time on stream. Postreaction catalyst characterization confirmed low levels of Ni and Cr deposition, although early-stage islanding of Ni-Sn will likely be problematic for industrially relevant time scales (i.e., thousands of hours). Overall, these results (i) demonstrate the performance of Ru-Sn/AC for aqueous phase succinic acid reduction, (ii) provide insight into the Ru-Sn bimetallic structure and deactivation in the presence of leached Ni, and (iii) underscore the importance of compatible reactor metallurgy and durable catalysts.}, number={9}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Vardon, Derek R. and Settle, Amy E. and Vorotnikov, Vassili and Menart, Martin J. and Eaton, Todd R. and Unocic, Kinga A. and Steirer, K. Xerxes and Wood, Kevin N. and Cleveland, Nicholas S. and Moyer, Kathleen E. and et al.}, year={2017}, month={Aug}, pages={6207–6219} }
 @article{pint_unocic_2017, title={Steam Oxidation Evaluation of Fe–Cr Alloys for Accident Tolerant Nuclear Fuel Cladding}, volume={87}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-017-9754-0}, DOI={10.1007/s11085-017-9754-0}, abstractNote={New nuclear fuel cladding materials are being evaluated that can withstand steam environments ≥1200 °C for short (≤4 h) periods in case of a beyond design basis accident. This study focused on commercial and model Fe–Cr alloys, where there is considerable experience in fabricating and joining. Exposures in 1 bar steam and air for 4 h at 800–1300 °C showed that the commercial Fe–Cr alloys were very sensitive to composition and only Fe-25.8%Cr-1%Mo formed a protective chromia scale at 1200 and 1300 °C in steam. A model Fe-22.5%Cr + Mn,Si,Y alloy also formed a protective scale at 1200 °C in steam. Analytical transmission electron microscopy of the reaction products revealed that (1) nominally equiaxed Cr2O3 formed at 1000–1200 °C; (2) at 1000 °C, there was a Mn inner and outer layer but at 1100 and 1200 °C only an outer layer was observed; (3) an amorphous SiO2 inner layer was observed at 1000 and 1100 °C, but the SiO2 was crystalline on the 22.5%Cr model alloy at 1200 °C, which was confirmed by electron and X-ray diffraction; and (4) Fe was found throughout the Cr2O3 formed on alloys without Mn at 1200 °C in steam and air, Fe-rich oxide near the gas interface and Fe-rich metal precipitates near the metal–oxide interface. A few Fe-rich precipitates were detected in oxides formed at 1100 °C and none at 1000 °C. The incorporation of Fe and crystallization of SiO2 at 1200 °C may be detrimental to the formation of a protective chromia scale in steam at ≥1200 °C for this application and explain why such high Cr contents are needed for protective behavior.}, number={3-4}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Pint, B. A. and Unocic, K. A.}, year={2017}, month={Mar}, pages={515–526} }
 @article{unocic_datye_bigelow_allard_2017, title={Water Vapor in Closed-Cell <i>In Situ</i> Gas Reactions: Initial Experiments}, volume={23}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927617005360}, DOI={10.1017/s1431927617005360}, abstractNote={Journal Article Water Vapor in Closed-Cell In Situ Gas Reactions: Initial Experiments Get access Kinga A Unocic, Kinga A Unocic Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Abhaya K Datye, Abhaya K Datye Chemical & Biological Engineering, University of New Mexico, Albuquerque, NM, USA Search for other works by this author on: Oxford Academic Google Scholar Wilbur C Bigelow, Wilbur C Bigelow Department of Materials Science & Engineering, University of Michigan, Ann Arbor, MI, USA Search for other works by this author on: Oxford Academic Google Scholar Lawrence F Allard Lawrence F Allard Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 23, Issue S1, 1 July 2017, Pages 940–941, https://doi.org/10.1017/S1431927617005360 Published: 04 August 2017}, number={S1}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A. and Datye, Abhaya K. and Bigelow, Wilbur C. and Allard, Lawrence F.}, year={2017}, month={Jul}, pages={940–941} }
 @article{unocic_pint_hoelzer_2016, title={Advanced TEM characterization of oxide nanoparticles in ODS Fe–12Cr–5Al alloys}, volume={51}, ISSN={0022-2461 1573-4803}, url={http://dx.doi.org/10.1007/s10853-016-0111-5}, DOI={10.1007/s10853-016-0111-5}, abstractNote={The oxide nanoparticles present in three oxide-dispersion-strengthened (ODS) Fe–12Cr–5Al alloys containing additions of (1) Y2O3 (125Y), (2) Y2O3 + ZrO2 (125YZ), and (3) Y2O3 + HfO2 (125YH), were investigated using transmission and scanning transmission electron microscopy. In all three alloys nano-sized (<3.5 nm) oxide particles distributed uniformly throughout the microstructure were characterized using advanced electron microscopy techniques. In the 125Y alloy, mainly Al2O3 and yttrium–aluminum garnet (YAG) phases (Y3Al5O12) were present, while in the 125YZ alloy, additional Zr(C,N) precipitates were identified. The 125YH alloy had the most complex precipitation sequence whereby in addition to the YAG and Al2O3 phases, Hf(C,N), Y2Hf2O7, and HfO2 precipitates were also found. The presence of HfO2 was mainly due to the incomplete incorporation of HfO2 powder during mechanical alloying of the 125YH alloy. The alloy having the highest total number density of the oxides, the smallest grain size, and the highest Vickers hardness was the 125YZ alloy indicating, that Y2O3 + ZrO2 additions had the strongest effect on grain size and tensile properties. High-temperature mechanical testing will be addressed in the near future, while irradiation studies are underway to investigate the irradiation resistance of these new ODS FeCrAl alloys.}, number={20}, journal={Journal of Materials Science}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Pint, Bruce A. and Hoelzer, David T.}, year={2016}, month={Jul}, pages={9190–9206} }
 @article{unocic_dryepondt_yamamoto_maziasz_2016, title={Creep and Oxidation Behavior of Modified CF8C-Plus with W, Cu, Ni, and Cr}, volume={47}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/s11661-016-3348-3}, DOI={10.1007/s11661-016-3348-3}, abstractNote={The microstructures of modified CF8C-Plus (Fe-19Cr-12Ni-0.4W-3.8Mn-0.2Mo-0.6Nb-0.5Si-0.9C) with W and Cu (CF8CPWCu) and CF8CPWCu enhanced with 21Cr + 15Ni or 22Cr + 17.5Ni were characterized in the as-cast condition and after creep testing. When imaged at lower magnifications, the as-cast microstructure was similar among all three alloys as they all contained a Nb-rich interdendritic phase and Mn-based inclusions. Transmission electron microscopy (TEM) analysis showed the presence of nanoscale Cu-rich nanoprecipitates distributed uniformly throughout the matrix of CF8CPWCu, whereas in CF8CPWCu22/17, Cu precipitates were found primarily at the grain boundaries. The presence of these nanoscale Cu-rich particles, in addition to W-rich Cr23C6, nanoscale Nb carbides, and Z-phase (Nb2Cr2N2), improved the creep strength of the CF8CPWCu steel. Modification of CF8CPWCu with Cr and Ni contents slightly decreased the creep strength but significantly improved the oxidation behavior at 1073 K (800 °C). In particular, the addition of 22Cr and 17.5Ni strongly enhanced the oxidation resistance of the stainless steel resulting in a 100 degrees or greater temperature improvement, and this composition provided the best balance between improving both mechanical properties and oxidation resistance.}, number={4}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Dryepondt, Sebastien and Yamamoto, Yukinori and Maziasz, Philip J.}, year={2016}, month={Feb}, pages={1641–1653} }
 @article{unocic_hoelzer_2016, title={Evaluation of Pb–17Li compatibility of ODS Fe-12Cr-5Al alloys}, volume={479}, url={https://doi.org/10.1016/j.jnucmat.2016.07.017}, DOI={10.1016/j.jnucmat.2016.07.017}, abstractNote={The Dual Coolant Lead Lithium (DCLL: eutectic Pb–17Li and He) blanket concept requires improved Pb–17Li compatibility with ferritic steels in order to demonstrate acceptable performance in fusion reactors. As an initial step, static Pb-17at.%Li (Pb-17Li) capsule experiments were conducted on new oxide dispersion strengthened (ODS) FeCrAl alloys ((1) Y2O3 (125Y), (2) Y2O3 + ZrO2 (125YZ), (3) Y2O3 + HfO2 (125YH), and (4) Y2O3 + TiO2 (125YT)) produced at ORNL via mechanical alloying (MA). Tests were conducted in static Pb–17Li for 1000 h at 700 °C. Alloys showed promising compatibility with Pb–17Li with small mass change after testing for 125YZ, 125YH and 125YT, while the 125Y alloy experienced the highest mass loss associated with some oxide spallation and subsequent alloy dissolution. X-ray diffraction methods identified the surface reaction product as LiAlO2 on all four alloys. A small decrease (∼1 at.%) in Al content beneath the oxide scale was observed in all four ODS alloys, which extended 60 μm beneath the oxide/metal interface. This indicates improvements in alloy dissolution by decreasing the amount of Al loss from the alloy. Scales formed on 125YZ, 125YH and 125YT were examined via scanning transmission electron microscopy (S/TEM) and revealed incorporation of Zr-, Hf-, and Ti-rich precipitates within the LiAlO2 product, respectively. This indicates an inward scale growth mechanism. Future work in flowing Pb–17Li is needed to further evaluate the effectiveness of this strategy in a test blanket module.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Unocic, Kinga A. and Hoelzer, David T.}, year={2016}, month={Oct}, pages={357–364} }
 @article{plotkowski_rios_sridharan_sims_unocic_ott_dehoff_babu_2017, title={Evaluation of an Al-Ce alloy for laser additive manufacturing}, volume={126}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2016.12.065}, DOI={10.1016/j.actamat.2016.12.065}, abstractNote={This study focuses on the development of a design methodology for alloys in AM, using a newly developed Al-Ce alloy as an initial case study. To evaluate the candidacy of this system for directed energy deposition processes, single-line laser melts were made on cast Al-12Ce plates using three different beam velocities (100, 200, and 300 mm/min). The microstructure was evaluated in the as-melted and heat treated conditions (24 h at 300 °C). An extremely fine microstructure was observed within the melt pools, evolving from eutectic at the outer solid-liquid boundaries to a primary Al FCC dendritic/cellular structure nearer the melt-pool centerline. The observed microstructures were rationalized through the construction of a microstructure selection map for the Al-Ce binary system, which will be used to enable future alloy design. Interestingly, the heat treated samples exhibited no microstructural coarsening.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Plotkowski, A. and Rios, O. and Sridharan, N. and Sims, Z. and Unocic, K. and Ott, R.T. and Dehoff, R.R. and Babu, S.S.}, year={2017}, month={Mar}, pages={507–519} }
 @article{sames_unocic_helmreich_kirka_medina_dehoff_babu_2017, title={Feasibility of in situ controlled heat treatment (ISHT) of Inconel 718 during electron beam melting additive manufacturing}, volume={13}, ISSN={2214-8604}, url={http://dx.doi.org/10.1016/j.addma.2016.09.001}, DOI={10.1016/j.addma.2016.09.001}, abstractNote={A novel technique was developed to control the microstructure evolution in Alloy 718 processed using Electron Beam Melting (EBM). In situ solution treatment and aging of Alloy 718 was performed by heating the top surface of the build after build completion scanning an electron beam to act as a planar heat source during the cool down process. Results demonstrate that the measured hardness (478 ± 7 HV) of the material processed using in situ heat treatment similar to that of peak-aged Inconel 718. Large solidification grains and cracks formed, which are identified as the likely mechanism leading to failure of tensile tests of the in situ heat treatment material under loading. Despite poor tensile performance, the technique proposed was shown to successively age Alloy 718 (increase precipitate size and hardness) without removing the sample from the process chamber, which can reduce the number of process steps in producing a part. Tighter controls on processing temperature during layer melting to lower process temperature and selective heating during in situ heat treatment to reduce over-sintering are proposed as methods for improving the process.}, journal={Additive Manufacturing}, publisher={Elsevier BV}, author={Sames, W.J. and Unocic, K.A. and Helmreich, G.W. and Kirka, M.M. and Medina, F. and Dehoff, R.R. and Babu, S.S.}, year={2017}, month={Jan}, pages={156–165} }
 @article{meyer_hijazi_bannister_unocic_garrison_parish_2016, title={Flux threshold measurements of He-ion beam induced nanofuzz formation on hot tungsten surfaces}, volume={T167}, ISSN={0031-8949 1402-4896}, url={http://dx.doi.org/10.1088/0031-8949/t167/1/014019}, DOI={10.1088/0031-8949/t167/1/014019}, abstractNote={We report measurements of the energy dependence of flux thresholds and incubation fluences for He-ion induced nano-fuzz formation on hot tungsten surfaces at UHV conditions over a wide energy range using real-time sample imaging of tungsten target emissivity change to monitor the spatial extent of nano-fuzz growth, corroborated by ex situ SEM and FIB/SEM analysis, in conjunction with accurate ion-flux profile measurements. The measurements were carried out at the multicharged ion research facility (MIRF) at energies from 218 eV to 8.5 keV, using a high-flux deceleration module and beam flux monitor for optimizing the decel optics on the low energy MIRF beamline. The measurements suggest that nano-fuzz formation proceeds only if a critical rate of change of trapped He density in the W target is exceeded. To understand the energy dependence of the observed flux thresholds, the energy dependence of three contributing factors: ion reflection, ion range and target damage creation, were determined using the SRIM simulation code. The observed energy dependence can be well reproduced by the combined energy dependences of these three factors. The incubation fluences deduced from first visual appearance of surface emissivity change were (2–4) × 1023 m−2 at 218 eV, and roughly a factor of 10 less at the higher energies, which were all at or above the displacement energy threshold. The role of trapping at C impurity sites is discussed.}, journal={Physica Scripta}, publisher={IOP Publishing}, author={Meyer, F W and Hijazi, H and Bannister, M E and Unocic, K A and Garrison, L M and Parish, C M}, year={2016}, month={Jan}, pages={014019} }
 @article{parish_unocic_tan_zinkle_kondo_snead_hoelzer_katoh_2017, title={Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys}, volume={483}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2016.10.038}, DOI={10.1016/j.jnucmat.2016.10.038}, abstractNote={We irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ∼50 dpa, ∼15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ∼8 nm, ∼1021 m−3 (CNA), and of ∼3 nm, 1023 m−3 (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces in all alloys survived ∼50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Parish, C.M. and Unocic, K.A. and Tan, L. and Zinkle, S.J. and Kondo, S. and Snead, L.L. and Hoelzer, D.T. and Katoh, Y.}, year={2017}, month={Jan}, pages={21–34} }
 @article{duan_jalowicka_unocic_pint_huczkowski_chyrkin_grüner_pillai_quadakkers_2016, title={Predicting Oxidation-Limited Lifetime of Thin-Walled Components of NiCrW Alloy 230}, volume={87}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-016-9653-9}, DOI={10.1007/s11085-016-9653-9}, abstractNote={Using alloy 230 as an example, a generalized oxidation lifetime model for chromia-forming Ni-base wrought alloys is proposed, which captures the most important damaging oxidation effects relevant for component design: wall thickness loss, scale spallation, and the occurrence of breakaway oxidation. For deriving input parameters and for verification of the model approach, alloy 230 specimens with different thicknesses were exposed for different times at temperatures in the range 950–1050 °C in static air. The studies focused on thin specimens (0.2–0.5 mm) to obtain data for critical subscale depletion processes resulting in breakaway oxidation within reasonably achievable test times up to 3000 h. The oxidation kinetics and oxidation-induced subscale microstructural changes were determined by combining gravimetric data with results from scanning electron microscopy with energy dispersive X-ray spectroscopy. The modeling of the scale spallation and re-formation was based on the NASA cyclic oxidation spallation program, while a new model was developed to describe accelerated oxidation occurring after longer exposure times in the thinnest specimens. The calculated oxidation data were combined with the reservoir model equation, by means of which the relation between the consumption and the remaining concentration of Cr in the alloy was established as a function of temperature and specimen thickness. Based on this approach, a generalized lifetime diagram is proposed, in which wall thickness loss is plotted as a function of time, initial specimen thickness, and temperature. The time to reach a critical Cr level at the scale/alloy interface of 10 wt% is also indicated in the diagrams.}, number={1-2}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Duan, R. and Jalowicka, A. and Unocic, K. and Pint, B. A. and Huczkowski, P. and Chyrkin, A. and Grüner, D. and Pillai, R. and Quadakkers, W. J.}, year={2016}, month={Oct}, pages={11–38} }
 @article{pint_unocic_allen haynes_2016, title={The Effect of Environment on Thermal Barrier Coating Lifetime}, volume={138}, ISSN={0742-4795 1528-8919}, url={http://dx.doi.org/10.1115/1.4032438}, DOI={10.1115/1.4032438}, abstractNote={While the water vapor content of the combustion gas in natural gas-fired land-based turbines is ∼10%, it can be 20–85% with coal-derived (syngas or H2) fuels or innovative turbine concepts for more efficient carbon capture. Additional concepts envisage working fluids with high CO2 contents to facilitate carbon capture and sequestration. To investigate the effects of changes in the gas composition on thermal barrier coating (TBC) lifetime, furnace cycling tests (1-h and 100-h cycles) were performed in air with 10, 50, and 90 vol. % water vapor and CO2-10% H2O and compared to prior results in dry air or O2. Two types of TBCs were investigated: (1) diffusion bond coatings (Pt-diffusion or Pt-modified aluminide) with commercial electron-beam physical vapor-deposited yttria-stabilized zirconia (YSZ) top coatings on second-generation superalloy N5 and N515 substrates and (2) high-velocity oxygen fuel (HVOF) sprayed MCrAlYHfSi bond coatings with air plasma-sprayed YSZ top coatings on superalloys X4, 1483, or 247 substrates. For both types of coatings exposed in 1-h cycles, the addition of water vapor resulted in a decrease in coating lifetime, except for Pt-diffusion coatings which were unaffected by the environment. In 100-h cycles, environment was less critical, perhaps because coating failure was chemical (i.e., due to interdiffusion) rather than mechanical. In both 1-h and 100-h cycles, CO2 did not appear to have any negative effect on coating lifetime.}, number={8}, journal={Journal of Engineering for Gas Turbines and Power}, publisher={ASME International}, author={Pint, Bruce A. and Unocic, Kinga A. and Allen Haynes, J.}, year={2016}, month={Mar} }
 @article{israelsson_unocic_hellström_jonsson_norell_svensson_johansson_2015, title={A Microstructural and Kinetic Investigation of the KCl-Induced Corrosion of an FeCrAl Alloy at 600 °C}, volume={84}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-015-9546-3}, DOI={10.1007/s11085-015-9546-3}, abstractNote={The corrosion behaviour of a FeCrAl alloy was investigated at 600 °C in O2 + H2O with solid KCl applied. A kinetics and microstructural investigation showed that KCl accelerates corrosion and that potassium chromate formation depletes the protective scale in Cr, thus triggering the formation of a fast-growing iron-rich scale. Iron oxide was found to grow both inward and outward, on either side of the initial oxide. A chromia layer is formed with time underneath the iron oxide. It was found that although the alloy does not form a continuous pure alumina scale at the investigated temperature, aluminium is, however, always enriched at the oxide/alloy interface.}, number={1-2}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Israelsson, N. and Unocic, K. A. and Hellström, K. and Jonsson, T. and Norell, M. and Svensson, J.-E. and Johansson, L.-G.}, year={2015}, month={Mar}, pages={105–127} }
 @article{allard_bigelow_wu_overbury_unocic_chi_carpenter_walden_thomas_gardiner_et al._2015, title={Computer-Controlled In Situ Gas Reactions via a MEMS-based Closed-Cell System}, volume={21}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927615001282}, DOI={10.1017/s1431927615001282}, abstractNote={Journal Article Computer-Controlled In Situ Gas Reactions via a MEMS-based Closed-Cell System Get access L F Allard, L F Allard Physical Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar W C Bigelow, W C Bigelow Department of Materials Science & Engineering, University of Michigan, Ann Arbor, MI, USA Search for other works by this author on: Oxford Academic Google Scholar Z Wu, Z Wu Physical Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar S H Overbury, S H Overbury Physical Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar K A Unocic, K A Unocic Physical Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar M Chi, M Chi Physical Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA Search for other works by this author on: Oxford Academic Google Scholar W B Carpenter, W B Carpenter Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar F S Walden, F S Walden Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar R L Thomas, R L Thomas Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar D S Gardiner, D S Gardiner Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar ... Show more B W Jacobs, B W Jacobs Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar D P Nackashi, D P Nackashi Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar J Damiano J Damiano Protochips, Inc., Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 97–98, https://doi.org/10.1017/S1431927615001282 Published: 23 September 2015}, number={S3}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Allard, L. F. and Bigelow, W. C. and Wu, Z. and Overbury, S. H. and Unocic, K. A. and Chi, M. and Carpenter, W. B. and Walden, F. S. and Thomas, R. L. and Gardiner, D. S. and et al.}, year={2015}, month={Aug}, pages={97–98} }
 @article{israelsson_unocic_hellström_svensson_johansson_2015, title={Cyclic Corrosion and Chlorination of an FeCrAl Alloy in the Presence of KCl}, volume={84}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-015-9554-3}, DOI={10.1007/s11085-015-9554-3}, abstractNote={The KCl-induced corrosion of the FeCrAl alloy Kanthal® APMT in an O2 + N2 + H2O environment was studied at 600 °C. The samples were pre-oxidized prior to exposure in order to investigate the protective nature of alumina scales in the present environment. The microstructure and composition of the corroded surface was investigated in detail. Corrosion started at flaws in the pre-formed α-alumina scales, i.e. α-alumina was protective in itself. Consequently, KCl-induced corrosion started locally and, subsequently, spread laterally. An electrochemical mechanism is proposed here by which a transition metal chloride forms in the alloy and K2CrO4 forms at the scale/gas interface. Scale de-cohesion is attributed to the formation of a sub-scale transition metal chloride.}, number={3-4}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Israelsson, N. and Unocic, K. A. and Hellström, K. and Svensson, J.-E. and Johansson, L.-G.}, year={2015}, month={May}, pages={269–290} }
 @article{pint_unocic_terrani_2015, title={Effect of steam on high temperature oxidation behaviour of alumina-forming alloys}, volume={32}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.1179/0960340914z.00000000058}, DOI={10.1179/0960340914z.00000000058}, abstractNote={Alternative light water reactor fuel cladding materials are being investigated to replace Zircaloy for enhanced accident tolerance, which involves oxidation resistance to steam environments at ≧1200°C for short times. As chromia-forming alloys and Ni-containing alloys are both undesirable for this application, the focus has been on FeCrAl, although NiAl was used to evaluate the effect of steam oxidation at 1600°C for this study. For commercial and model FeCrAlY alloys, a critical Cr–Al composition was identified for 1 bar isothermal steam (100% H2O) oxidation resistance at 1200°C, which differed for exposures in Ar–50%H2O at the same temperature. Alloys with lower Cr and Al contents were not able to form a protective alumina scale under these conditions. To simulate the accident scenario, exposures were also conducted in steam with the temperature rising 5°C min−1 to 1500°C for the most oxidation resistant alloys. Using thermogravimetry, the maximum use temperature for candidate alloys was determined for different Cr and Al contents. Minor additions such as Y and Ti appeared to be beneficial for oxidation resistance. Similar to prior studies, alumina scales formed in air and in steam appeared to have only subtle differences in microstructure.}, number={1-2}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Pint, B. A. and Unocic, K. A. and Terrani, K. A.}, year={2015}, month={Jan}, pages={28–35} }
 @article{brady_rother_anovitz_littrell_unocic_elsentriecy_song_thomson_gallego_davis_2015, title={Film Breakdown and Nano-Porous Mg(OH)<sub>2</sub>Formation from Corrosion of Magnesium Alloys in Salt Solutions}, volume={162}, ISSN={0013-4651 1945-7111}, url={http://dx.doi.org/10.1149/2.0171504jes}, DOI={10.1149/2.0171504jes}, abstractNote={Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) and ZE10A (Elektron 717, E717: Mg-1Zn + Nd, Zr) in H2O and D2O with and without 1 or 5 wt% NaCl. No SANS scattering changes were observed after 24 h D2O or H2O exposures compared with as-received (unreacted) alloy, consistent with relatively dense MgO-base film formation. However, exposure to 5 wt% NaCl resulted in accelerated corrosion, with resultant SANS scattering changes detected. The SANS data indicated both particle and rough surface (internal and external) scattering, but with no preferential size features. The films formed in 5 wt% NaCl consisted of a thin, inner MgO-base layer, and a nano-porous and filamentous Mg(OH)2 outer region tens of microns thick. Chlorine was detected extending to the inner MgO-base film region, with segregation of select alloying elements also observed in the inner MgO, but not the outer Mg(OH)2. Modeling of the SANS data suggested that the outer Mg(OH)2 films had very high surface areas, consistent with loss of film protectiveness. Implications for the NaCl corrosion mechanism, and the potential utility of SANS for Mg corrosion, are discussed.}, number={4}, journal={Journal of The Electrochemical Society}, publisher={The Electrochemical Society}, author={Brady, M. P. and Rother, G. and Anovitz, L. M. and Littrell, K. C. and Unocic, K. A. and Elsentriecy, H. H. and Song, G.-L. and Thomson, J. K. and Gallego, N. C. and Davis, B.}, year={2015}, pages={C140–C149} }
 @article{unocic_hoelzer_pint_2015, title={Microstructure and environmental resistance of low Cr ODS FeCrAl}, volume={32}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.1179/0960340914z.00000000088}, DOI={10.1179/0960340914z.00000000088}, abstractNote={Three oxide dispersion strengthened (ODS) Fe–12 wt-%Cr–5 wt-%Al (12 at-%Cr–9·7 at-%Al) alloys were mechanically alloyed with different oxide additions: (1) Y2O3, (2) Y2O3+HfO2 and (3) Y2O3+ZrO2. The as extruded microstructure was characterised including the oxide particle composition and size distribution. The 700°C Pb–Li compatibility was evaluated for a fusion energy application and the steam oxidation resistance at 1200°C and higher temperatures was evaluated for a nuclear accident tolerant fuel cladding application. The alloy prepared with only a Y2O3 addition contained some low Al regions and did not perform well, but provided a baseline for comparison. The other alloys contained sufficient Cr and Al to form a protective LiAlO2 surface oxide, which inhibits dissolution in isothermal Pb–Li. Also, a protective α-Al2O3 scale formed in steam oxidation at 1200°C, similar to the scale formed in dry air at 1200°C. For the alloy with HfO2, the scale remained protective to 1475°C in steam.}, number={1-2}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Unocic, K. A. and Hoelzer, D. T. and Pint, B. A.}, year={2015}, month={Jan}, pages={123–132} }
 @article{unocic_baggetto_veith_aguiar_unocic_sacci_dudney_more_2015, title={Probing battery chemistry with liquid cell electron energy loss spectroscopy}, volume={51}, ISSN={1359-7345 1364-548X}, url={http://dx.doi.org/10.1039/c5cc07180a}, DOI={10.1039/c5cc07180a}, abstractNote={We demonstrate the ability to apply electron energy loss spectroscopy (EELS) to follow the chemistry and oxidation states of LiMn2O4 and Li4Ti5O12 battery electrodes within a battery solvent. This is significant as the use and importance of in situ electrochemical cells coupled with a scanning/transmission electron microscope (S/TEM) has expanded and been applied to follow changes in battery chemistry during electrochemical cycling. We discuss experimental parameters that influence measurement sensitivity and provide a framework to apply this important analytical method to future in situ electrochemical studies.}, number={91}, journal={Chemical Communications}, publisher={Royal Society of Chemistry (RSC)}, author={Unocic, Raymond R. and Baggetto, Loïc and Veith, Gabriel M. and Aguiar, Jeffery A. and Unocic, Kinga A. and Sacci, Robert L. and Dudney, Nancy J. and More, Karren L.}, year={2015}, pages={16377–16380} }
 @article{atkinson_st. john_dyck_unocic_unocic_burke_cisco_rice_zawodzinski_papandrew_2015, title={Supportless, Bismuth-Modified Palladium Nanotubes with Improved Activity and Stability for Formic Acid Oxidation}, volume={5}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/acscatal.5b01239}, DOI={10.1021/acscatal.5b01239}, abstractNote={Palladium nanotubes (PdNTs) were synthesized by templated vapor deposition and investigated for formic acid electrooxidation. Annealed PdNTs are 2.4 times more active (2.19 mA/cm2) than commercial carbon-supported palladium (0.91 mA/cm2) at 0.3 V vs RHE. Bismuth modification improved nanotube performance over 4 times (3.75 mA/cm2) vs Pd/C and nearly 2 times vs unmodified PdNTs. A surface Bi coverage of 80% results in optimal site-specific activity by drastically reducing surface-poisoning CO generation during formic acid electrooxidation. The Bi-modified PdNTs are exceptionally stable, maintaining 2 times the area-normalized current density as Pd/C after 24 h at 0.2 V vs RHE. We attribute the enhanced activity and stability of the nanotube catalysts to the presence of highly coordinated surfaces, mimicking a flat polycrystal while retaining high surface area geometry.}, number={9}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Atkinson, Robert W., III and St. John, Samuel and Dyck, Ondrej and Unocic, Kinga A. and Unocic, Raymond R. and Burke, Colten S. and Cisco, Joshua W. and Rice, Cynthia A. and Zawodzinski, Thomas A., Jr. and Papandrew, Alexander B.}, year={2015}, month={Aug}, pages={5154–5163} }
 @article{song_unocic_2015, title={The anodic surface film and hydrogen evolution on Mg}, volume={98}, ISSN={0010-938X}, url={http://dx.doi.org/10.1016/j.corsci.2015.05.047}, DOI={10.1016/j.corsci.2015.05.047}, abstractNote={This study clarifies that the inner and outer layers of the anodic film consist of a nano/micro-porous MgO + Mg(OH)2 mixture. The film becomes thicker and more porous with increasing potential. It can rupture when potential is too positive in a non-corrosive Mg(OH)2 solution. Hydrogen evolution becomes more intensive as polarization potential increases, particularly when the potential at the film-covered Mg surface is close to or more positive than the hydrogen equilibrium potential, suggesting that an “anodic hydrogen evolution” (AHE) reaction occurs on the substrate Mg in film pores, and the significantly intensified AHE causes film rupture at high potential.}, journal={Corrosion Science}, publisher={Elsevier BV}, author={Song, Guang-Ling and Unocic, Kinga A.}, year={2015}, month={Sep}, pages={758–765} }
 @article{taborga claure_chai_dai_unocic_alamgir_agrawal_jones_2015, title={Tuning of higher alcohol selectivity and productivity in CO hydrogenation reactions over K/MoS2 domains supported on mesoporous activated carbon and mixed MgAl oxide}, volume={324}, ISSN={0021-9517}, url={http://dx.doi.org/10.1016/j.jcat.2015.01.015}, DOI={10.1016/j.jcat.2015.01.015}, abstractNote={Higher alcohol synthesis from syngas is studied over K/MoS2 domains supported on mesoporous carbon (C), mixed MgAl oxide (MMO), or mixtures thereof. While the carbon support offers high ethanol productivity, the MMO support yields enhanced C3+OH selectivity. MoKMMO-C, whereby Mo is initially contained on MMO then ground with carbon, behaves similar to the parent MoKMMO catalyst, as Mo on MMO has limited mobility during reaction. In contrast, on MoKC-MMO, significant Mo migrates from C to MMO during reaction, giving reactivity associated with Mo species on both supports (high C3+OH selectivity and productivity). MoS2 domain structures are correlated with the selectivity of the catalysts (C3+OH selectivity ∼ double MoS2 layers, total hydrocarbon selectivity ∼ single MoS2 layers). This study advances the understanding of the support’s effect on structure–reactivity relationships for this family of catalysts and introduces a new catalyst composition with desirable reactivity.}, journal={Journal of Catalysis}, publisher={Elsevier BV}, author={Taborga Claure, Micaela and Chai, Song-Hai and Dai, Sheng and Unocic, Kinga A. and Alamgir, Faisal M. and Agrawal, Pradeep K. and Jones, Christopher W.}, year={2015}, month={Apr}, pages={88–97} }
 @article{atkinson_unocic_unocic_veith_zawodzinski_papandrew_2015, title={Vapor Synthesis and Thermal Modification of Supportless Platinum–Ruthenium Nanotubes and Application as Methanol Electrooxidation Catalysts}, volume={7}, ISSN={1944-8244 1944-8252}, url={http://dx.doi.org/10.1021/am508228b}, DOI={10.1021/am508228b}, abstractNote={Metallic, mixed-phase, and alloyed bimetallic Pt–Ru nanotubes were synthesized by a novel route based on the sublimation of metal acetylacetonate precursors and their subsequent vapor deposition within anodic alumina templates. Nanotube architectures were tuned by thermal annealing treatments. As-synthesized nanotubes are composed of nanoparticulate, metallic platinum and hydrous ruthenium oxide whose respective thicknesses depend on the sample chemical composition. The Pt-decorated, hydrous Ru oxide nanotubes may be thermally annealed to promote a series of chemical and physical changes to the nanotube structures, including alloy formation, crystallite growth, and morphological evolution. Annealed Pt–Ru alloy nanotubes and their as-synthesized analogs demonstrate relatively high specific activities for the oxidation of methanol. As-synthesized, mixed-phase Pt–Ru nanotubes (0.39 mA/cm2) and metallic alloyed Pt64Ru36NTs (0.33 mA/cm2) have considerably higher area-normalized activities than PtRu black (0.22 mA/cm2) at 0.65 V vs RHE.}, number={19}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Atkinson, Robert W., III and Unocic, Raymond R. and Unocic, Kinga A. and Veith, Gabriel M. and Zawodzinski, Thomas A., Jr. and Papandrew, Alexander B.}, year={2015}, month={May}, pages={10115–10124} }
 @article{unocic_pint_2014, title={Alloying and coating strategies for improved Pb–Li compatibility in DEMO-type fusion reactors}, volume={455}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2014.06.058}, DOI={10.1016/j.jnucmat.2014.06.058}, abstractNote={Two strategies were explored to improve the Pb–16Li compatibility of Fe-base alloys for a fusion energy blanket system. The use of thin (∼50 μm) Al-rich diffusion coatings on Grade 92 (9Cr–2W) substrates significantly reduced the mass loss in static Pb–Li capsule tests for up to 5000 h at 600 °C and 700 °C. However, significant Al loss was observed at 700 °C. Thicker coatings with Fe–Al intermetallic layers partially spalled after exposure at 700 °C, suggesting that coating strategies are limited to lower temperatures. To identify compositions for further alloy development, model FeCrAlY alloys with 10–20 wt.%Cr and 3–5%Al were exposed for 1000 h at 700 °C. There was little effect on mass change of varying the Cr content, however, alloys with <5% Al showed mass losses in these experiments. For both coatings and FeCrAl alloys, the surface reaction product was LiAlO2 after exposure and cleaning.}, number={1-3}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Unocic, K.A. and Pint, B.A.}, year={2014}, month={Dec}, pages={330–334} }
 @article{barr_vetterick_unocic_hattar_bai_taheri_2014, title={Anisotropic radiation-induced segregation in 316L austenitic stainless steel with grain boundary character}, volume={67}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/j.actamat.2013.11.060}, DOI={10.1016/j.actamat.2013.11.060}, abstractNote={Radiation-induced segregation (RIS) and subsequent depletion of chromium along grain boundaries has been shown to be an important factor in irradiation-assisted stress corrosion cracking in austenitic face-centered cubic (fcc)-based alloys used for nuclear energy systems. A full understanding of RIS requires examination of the effect of the grain boundary character on the segregation process. Understanding how specific grain boundary structures respond under irradiation would assist in developing or designing alloys that are more efficient at removing point defects, or reducing the overall rate of deleterious Cr segregation. This study shows that solute segregation is dependent not only on grain boundary misorientation, but also on the grain boundary plane, as highlighted by markedly different segregation behavior for the Σ3 incoherent and coherent grain boundaries. The link between RIS and atomistic modeling is also explored through molecular dynamic simulations of the interaction of vacancies at different grain boundary structures through defect energetics in a simple model system. A key insight from the coupled experimental RIS measurements and corresponding defect–grain boundary modeling is that grain boundary–vacancy formation energy may have a critical threshold value related to the major alloying elements’ solute segregation.}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Barr, Christopher M. and Vetterick, Gregory A. and Unocic, Kinga A. and Hattar, Khalid and Bai, Xian-Ming and Taheri, Mitra L.}, year={2014}, month={Apr}, pages={145–155} }
 @article{pint_dryepondt_unocic_hoelzer_2014, title={Development of ODS FeCrAl for Compatibility in Fusion and Fission Energy Applications}, volume={66}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/s11837-014-1200-z}, DOI={10.1007/s11837-014-1200-z}, abstractNote={Oxide dispersion strengthened (ODS) FeCrAl alloys with 12–15% Cr are being evaluated for improved compatibility with Pb-Li for a fusion energy application and with high temperature steam for a more accident-tolerant light water reactor fuel cladding application. A 12% Cr content alloy showed low mass losses in static Pb-Li at 700°C, where a LiAlO2 surface oxide formed and inhibited dissolution into the liquid metal. All the evaluated compositions formed a protective scale in steam at 1200°C, which is not possible with ODS FeCr alloys. However, most of the compositions were not protective at 1400°C, which is a general and somewhat surprising problem with ODS FeCrAl alloys that is still being studied. More work is needed to optimize the alloy composition, microstructure and oxide dispersion, but initial promising tensile and creep results have been obtained with mixed oxide additions, i.e. Y2O3 with ZrO2, HfO2 or TiO2.}, number={12}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Pint, B. A. and Dryepondt, S. and Unocic, K. A. and Hoelzer, D. T.}, year={2014}, month={Nov}, pages={2458–2466} }
 @misc{unocic_pint_2014, title={Effect of Environment on the High Temperature Oxidation Behavior of 718 and 718Plus}, url={http://dx.doi.org/10.7449/2014/superalloys_2014_667_677}, DOI={10.7449/2014/superalloys_2014_667_677}, abstractNote={Ni-base alloys 718 and 718Plus are widely used for high temperature components in aircraft and power generation turbines under various environment conditions.Laboratory experimental rigs were used to simulate turbine exhaust (air with 10%H2O), steam and laboratory air at 550°-800°C for up to 10,000 h and compared to oxidation in laboratory air.Because component lifetimes can be much longer than 10,000 h, the experiments at 800°C were performed in an attempt to simulate longer exposures at lower temperatures but there are concerns about 718 microstructural stability at this temperature.Oxidation in wet air resulted in net mass losses due to the formation of volatile CrO2(OH)2 but Cr depletion in the substrate was minimal, even at 800°C.The rate constants for 718Plus in air tended to be slightly lower than 718 but otherwise few differences in oxidation behavior were observed.The higher Al content in 718Plus or the finer grain size in these specimens may help to reduce the reaction rate.}, journal={8th International Symposium on Superalloy 718 and Derivatives (2014)}, publisher={John Wiley & Sons, Inc.}, author={Unocic, K. and Pint, B.}, year={2014}, pages={667–677} }
 @article{unocic_leonard_pint_2014, title={Effect of boron on the oxidation behavior of NiCrAlYHfTi in H2O and CO2 environments}, volume={260}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2014.06.074}, DOI={10.1016/j.surfcoat.2014.06.074}, abstractNote={Cast NiCrAl alloys, co-doped with Y, Hf, Ti, and/or B, were evaluated at 1100 °C and 1150 °C in dry air, wet air (10 or 50% H2O), and CO2–10% H2O, in order to study the effect of boron additions on alumina scale growth and adhesion. After 200, 1-h cycles at 1100 °C, all of the alloys with Y and Hf showed good scale adhesion. By increasing the test temperature to 1150 °C, the addition of ~ 0.3 at.% (0.07 wt.%) B was shown to improve alumina scale adhesion during 1-h cycles in air with 10% H2O. Analytical transmission electron microscopy showed no effect of B on the alumina scale microstructure and only minor effects on the depth of internal oxidation at 1100 °C. Combined Ti and B additions did not produce an additional benefit and Cr–B precipitates were detected in both B-doped alloys. Exposures in O2-buffered CO2–H2O did not result in any detrimental effect at 1100 °C.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Unocic, K.A. and Leonard, D.N. and Pint, B.A.}, year={2014}, month={Dec}, pages={17–22} }
 @article{nordhorn_mücke_unocic_lance_pint_vaßen_2014, title={Effects of thermal cycling parameters on residual stresses in alumina scales of CoNiCrAlY and NiCoCrAlY bond coats}, volume={258}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2014.08.028}, DOI={10.1016/j.surfcoat.2014.08.028}, abstractNote={Furnace cycling experiments were performed on free-standing high-velocity oxygen-fuel bond coat samples to investigate the effect of material composition, surface texture, and cycling conditions on the average stresses in the formed oxide scales after cooling. The oxide scale thicknesses were determined by SEM image analyses and information about the stresses were acquired by photo-stimulated luminescence-spectroscopy. Additionally, the scale thickness dependent stress fields were calculated in finite-element analyses including approximation functions for the surface roughness derived on the basis of profilometry data. The evolution of the average residual stress as a function of oxide scale thickness was subject to stochastic fluctuations predominantly caused by local scale spallations. In comparison to the supplemental modeling results, thermal stresses due to mismatch of thermal expansion coefficients are identified as the main contribution to the residual stresses. The theoretical results emphasize that analyses of spectroscopic data acquired for average stress investigations of alumina scales rely on detailed information about microstructural features.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Nordhorn, Christian and Mücke, Robert and Unocic, Kinga A. and Lance, Michael J. and Pint, Bruce A. and Vaßen, Robert}, year={2014}, month={Nov}, pages={608–614} }
 @inproceedings{unocic_kolbus_dehoff_dryepondt_pint_2014, title={High-Temperature Oxidation Behavior of Alloy 718 Processed by Additive Manufacturing}, number={4478}, booktitle={Conference Proceedings, CORROSION 2014, NACE International}, author={Unocic, K.A. and Kolbus, L.M. and Dehoff, R.R. and Dryepondt, Sebastien N. and Pint, B.A.}, year={2014} }
 @inproceedings{tortorelli_wang_unocic_santella_shingledecker_cedro_2014, title={Long-Term Creep-Rupture Behavior of Inconel® 740 and Haynes® 282}, url={http://dx.doi.org/10.1115/etam2014-1003}, DOI={10.1115/etam2014-1003}, abstractNote={Creep testing and microstructural analysis were used to assess the properties and time-dependent deformation behavior of precipitation-strengthened nickel-based alloys, specifically, Inconel® alloy 740 and Haynes® 282® alloy, for use as pressure components in boilers operating under advanced steam conditions (750°C, >35 MPa). In support of the need for extended service of steam boiler tubing, piping and vessels, the ability of simple Larson-Miller estimates and a modified power-law model (Wilshire et al.) to predict creep lifetimes on the order of 105 hours based on experimental data out to almost 50,000 h was evaluated for these alloys. Even under conservative conditions, both Inconel alloy 740 and Haynes 282 project to have creep lifetimes exceeding 100,000 hours at 750°C and 100 MPa. Paper published with permission.}, booktitle={ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries}, publisher={American Society of Mechanical Engineers}, author={Tortorelli, P. F. and Wang, H. and Unocic, K. A. and Santella, M. L. and Shingledecker, J. P. and Cedro, V., III}, year={2014}, month={Mar}, pages={29–36} }
 @article{unocic_shingledecker_tortorelli_2014, title={Microstructural Changes in Inconel® 740 After Long-Term Aging in the Presence and Absence of Stress}, volume={66}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/s11837-014-1208-4}, DOI={10.1007/s11837-014-1208-4}, abstractNote={The Ni-based alloy, Inconel® 740, is being extensively examined for use in advanced ultrasupercritical steam boilers because its precipitation-strengthened microstructure appears to offer the necessary creep strength under the high temperatures and pressures (up to 760°C and 35 MPa) needed for high efficiency power generation. However, because this application requires extremely long lifetimes under these conditions (up to 30 years), long-term microstructure stability is a major concern. In this paper, results from microstructural analyses of Inconel 740 specimens aged at 700 and 750°C in the presence and absence of creep loading for times up to ~31,000 h are presented. The primary focus was on the development of the eta η (Ni3Ti) phase and coarsening of coherent γ′-Ni3(Al,Ti) precipitates and its depletion near eta/matrix interfaces. However, despite these processes, Inconel 740 showed adequate long-term microstructural stability to assure adequate creep strength for the intended application.}, number={12}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Unocic, K. A. and Shingledecker, J. P. and Tortorelli, P. F.}, year={2014}, month={Nov}, pages={2535–2542} }
 @article{unocic_allard_coffey_more_unocic_2014, title={Novel Method for Precision Controlled Heating of TEM Thin Sections to Study Reaction Processes}, volume={20}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927614009878}, DOI={10.1017/s1431927614009878}, abstractNote={An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.}, number={S3}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, Kinga A. and Allard, Lawrence F. and Coffey, Dorothy W. and More, Karren L. and Unocic, Raymond R.}, year={2014}, month={Aug}, pages={1628–1629} }
 @article{rouaix-vande put_unocic_brady_pint_2015, title={Performance of chromia- and alumina-forming Fe- and Ni-base alloys exposed to metal dusting environments: The effect of water vapor and temperature}, volume={92}, ISSN={0010-938X}, url={http://dx.doi.org/10.1016/j.corsci.2014.11.022}, DOI={10.1016/j.corsci.2014.11.022}, abstractNote={Fe- and Ni-base alloys including an alumina-forming austenitic alloy were exposed for 500 h under metal dusting environments with varying temperature, gas composition and total pressure. For one H2–CO–CO2–H2O environment, the increase in temperature from 550 to 750 °C generally decreased metal dusting. When H2O was added to a H2–CO–CO2 environment at 650 °C, the metal dusting attack was reduced. Even after 5000 h at a total pressure of 9.1 atm with 20%H2O, the higher alloyed specimens retained a thin protective oxide. For gas mixtures containing little or no H2O, the Fe-base alloys were less resistant to metal dusting than Ni-base alloys.}, journal={Corrosion Science}, publisher={Elsevier BV}, author={Rouaix-Vande Put, Aurelie and Unocic, Kinga A. and Brady, Michael P. and Pint, Bruce A.}, year={2015}, month={Mar}, pages={58–68} }
 @article{lance_unocic_haynes_pint_2014, title={The effect of cycle frequency, H2O and CO2 on TBC lifetime with NiCoCrAlYHfSi bond coatings}, volume={260}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2014.08.082}, DOI={10.1016/j.surfcoat.2014.08.082}, abstractNote={Furnace cycle testing of superalloy 1483 and X4 substrates with high velocity oxygen fuel (HVOF) NiCoCrAlYHfSi bond coatings and air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) top coatings was conducted at 1100 °C in various environments. Average thermal barrier coating (TBC) lifetimes were 5–6 times longer when 100 h cycles were used to simulate base-load power generation operation, compared to the 1 h aero-engine standard cycle. Longer exposure times for 100 h cycles increased the interdiffusion resulting in no clear effects of H2O and CO2 additions on average TBC lifetime for the 1483 substrates, contrary to the results with 1 h cycles where the addition of H2O reduced TBC lifetime. The lower Al content and perhaps the higher Ti content in 1483 compared to X4 resulted in lower TBC lifetimes for 1483. Photo-stimulated luminescence piezospectroscopy (PLPS) and 3D microscopy were used to measure residual stress in the alumina scale and surface roughness, respectively, on specimens with and without a YSZ top coating.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Lance, M.J. and Unocic, K.A. and Haynes, J.A. and Pint, B.A.}, year={2014}, month={Dec}, pages={107–112} }
 @article{sames_unocic_dehoff_lolla_babu_2014, title={Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting}, volume={29}, ISSN={0884-2914 2044-5326}, url={http://dx.doi.org/10.1557/jmr.2014.140}, DOI={10.1557/jmr.2014.140}, number={17}, journal={Journal of Materials Research}, publisher={Springer Science and Business Media LLC}, author={Sames, William J. and Unocic, Kinga A. and Dehoff, Ryan R. and Lolla, Tapasvi and Babu, Sudarsanam S.}, year={2014}, month={Jul}, pages={1920–1930} }
 @article{brady_fayek_elsentriecy_unocic_anovitz_keiser_song_davis_2014, title={Tracer Film Growth Study of Hydrogen and Oxygen from the Corrosion of Magnesium in Water}, volume={161}, ISSN={0013-4651 1945-7111}, url={http://dx.doi.org/10.1149/2.0821409jes}, DOI={10.1149/2.0821409jes}, abstractNote={An isotopic tracer study of the film growth mechanism for pure magnesium, AZ31B, and ZE10A (Elektron 717, E717) magnesium alloys in water at room temperature was performed. A series of individual and sequential exposures were conducted in both H218O and D216O, with isotopic tracer profiles obtained using secondary ion mass spectrometry (SIMS). The water-formed films consisted primarily of partially hydrated MgO. The SIMS sputter depth profiles indicate that H and D penetrated throughout the film and into the underlying metal, particularly for the Zr- and Nd-containing E717 alloy. Film growth for the UHP Mg involved aspects of both metal outward diffusion and oxygen/hydrogen inward diffusion. In contrast, the film on the Al-containing AZ31B alloy grew primarily by inward oxygen and inward hydrogen diffusion. The 18O and D profiles for the film formed on E717 were the most complex, with the 18O data most consistent with inward lattice oxygen diffusion, but the D data suggests inward, short-circuit diffusion through the film. It is speculated that preferential inward short circuit hydrogen transport may have been aided by the presence of nano Zn2Zr3 particles throughout the E717 film. Such hydrogen penetration may have implications from both a corrosion resistance and hydrogen storage perspective.}, number={9}, journal={Journal of The Electrochemical Society}, publisher={The Electrochemical Society}, author={Brady, M. P. and Fayek, M. and Elsentriecy, H. H. and Unocic, K. A. and Anovitz, L. M. and Keiser, J. R. and Song, G. L. and Davis, B.}, year={2014}, pages={C395–C404} }
 @article{unocic_elsentriecy_brady_meyer_song_fayek_meisner_davis_2014, title={Transmission Electron Microscopy Study of Aqueous Film Formation and Evolution on Magnesium Alloys}, volume={161}, ISSN={0013-4651 1945-7111}, url={http://dx.doi.org/10.1149/2.024406jes}, DOI={10.1149/2.024406jes}, abstractNote={The films formed on ultrahigh purity Mg, Elektron 717 (ZE10A), and AZ31B in water at room temperature were characterized by TEM, XPS, and SIMS. The films consisted primarily of MgO, with surface regions also containing Mg(OH)2 and MgCO3. SIMS suggested H throughout the films and into the underlying metal. Segregation of Zn to the metal/film interface and Al in the film was observed for AZ31B. Similar Zn film segregation was also detected for Elektron 717, along with Nd at the alloy/film interface and nano-size Zn2Zr3 precipitates throughout the film. Implications of these findings on film growth are discussed.}, number={6}, journal={Journal of The Electrochemical Society}, publisher={The Electrochemical Society}, author={Unocic, K. A. and Elsentriecy, H. H. and Brady, Michael P. and Meyer, H. M., III and Song, G. L. and Fayek, M. and Meisner, R. A. and Davis, B.}, year={2014}, pages={C302–C311} }
 @article{unocic_lance_pint_2013, title={Characterization of specimens exposed in a Li loop}, volume={442}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2013.04.055}, DOI={10.1016/j.jnucmat.2013.04.055}, abstractNote={A monometallic V–4Cr–4Ti thermal convection loop was run for 2355 h with a peak temperature of 700 °C (973 K) and Li flow rate of 2–3 cm/s. Specimens of V–4Cr–4Ti exposed in the hot and cold legs of the loop and tensile tested in vacuum at 500 °C (773 K) showed an increase in the 0.2% yield and ultimate tensile strengths and a decrease in the serration amplitude with decreasing exposure temperature in the loop. However, only minor changes in ductility were measured. With the higher temperature exposures, a decrease in Vickers hardness was measured, but little change in the grain size was observed. Characterization of the microstructure after exposure at 627 °C (900 K) in the loop showed an increase in the density of Ti- and N-rich grain boundary and matrix precipitates near the specimen surface after exposure corresponding to an increase in the hardness in the near-surface region. Two-layer V/Y2O3 coatings on V–4Cr–4Ti substrates also were exposed in the loop, and initial room temperature characterization was conducted.}, number={1-3}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Unocic, K.A. and Lance, M.J. and Pint, B.A.}, year={2013}, month={Nov}, pages={S580–S584} }
 @inproceedings{tortorelli_unocic_wang_santella_shingledecker_2013, title={Creep-Rupture Behavior of Precipitation-Strengthened Ni-Based Alloys Under Advanced Ultrasupercritical Steam Conditions}, volume={84666}, ISSN={2994-4031 2994-4023}, url={http://dx.doi.org/10.31399/asm.cp.am-epri-2013p0131}, DOI={10.31399/asm.cp.am-epri-2013p0131}, abstractNote={Abstract To achieve the necessary creep-rupture lifetimes at the temperatures and pressures associated with advanced ultrasupercritical (A-USC) steam conditions (100,000 h at 100 MPa and 760°C), precipitation-strengthened nickel-based alloys are required for the superheater and reheater tubing in A-USC boilers. Two alloys were considered to have potential for this application: Inconel 740 and Haynes 282 alloy. In support of this application, creep-rupture testing of several heats of Inconel 740 was conducted over a range of temperatures and stresses to develop confidence in qualitatively predicting creep lifetimes under conditions relevant to A-USC steam conditions, with the longest rupture times exceeding 30,000 h. For comparison, the creep-rupture behavior of Haynes 282 alloy was mapped as a function of temperature and stress, but with a significantly smaller dataset. Only a small difference in creep-rupture results between Inconel 740 and Inconel 740H was found although the latter alloy showed significantly greater resistance to η phase formation during testing. Little effect of prior aging treatments (for setting the γ′ precipitate structure) on creep-rupture behavior was observed. Results from a modified power law analysis showed that, while both Inconel 740 and Haynes 282 are projected to meet the A-USC lifetime requirements, the latter offered the potential for better long-term creep resistance.}, booktitle={Advances in Materials Technology for Power Plants}, publisher={ASM International}, author={Tortorelli, P.F. and Unocic, K.A. and Wang, H. and Santella, M.L. and Shingledecker, J.P}, editor={Gandy, D. and Shingledecker, J.Editors}, year={2013}, month={Oct}, pages={131–142} }
 @article{lance_unocic_haynes_pint_2013, title={Effect of water vapor on thermally-grown alumina scales on Pt-modified and simple aluminide bond coatings}, volume={237}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2013.06.041}, DOI={10.1016/j.surfcoat.2013.06.041}, abstractNote={Photo-stimulated luminescence spectroscopy (PSLS), 3D microscopy and focused ion beam cross-sections were used to study the effect of water vapor on the cyclic (1 h cycle time) oxidation behavior of simple and Pt-modified aluminide bond coatings on several superalloy substrates at 1125° and 1150 °C. By tracking the same region over time, the change in surface roughness with thermal cycling could be attributed to large and small bond coating grains rising and sinking, respectively, with thermal cycling. Oxidation in air with 10% H2O showed a 0–37% increase in surface roughness compared to oxidation in dry air. Reducing the cycle temperature from 1150° to 1125 °C, increased the thermal barrier coating lifetime by > 4X but did not prevent bond coating rumpling. Compared to oxidation in dry air, PSLS identified more θ-Al2O3 formation on the Pt-modified aluminide bond coatings after 1 h at 1125° or 1150 °C in air with 10% H2O but only minor differences in the residual stress after longer cyclic oxidation exposures. Stress histograms produced by PSLS mapping help to elucidate Al2O3 scale damage accumulation in each condition but did not clearly identify a mechanism for the effect of water vapor on coating performance.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Lance, M.J. and Unocic, K.A. and Haynes, J.A. and Pint, B.A.}, year={2013}, month={Dec}, pages={2–7} }
 @article{haynes_unocic_lance_pint_2013, title={Impact of superalloy composition, bond coat roughness and water vapor on TBC lifetime with HVOF NiCoCrAlYHfSi bond coatings}, volume={237}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2013.09.062}, DOI={10.1016/j.surfcoat.2013.09.062}, abstractNote={The performance of thermal barrier coating (TBC) specimens with superalloy 1483 and X4 substrates and high velocity oxy fuel (HVOF)-NiCoCrAlYHfSi bond coatings was evaluated in dry and wet air in 1 h furnace cycles at 1100 °C. Compared to a prior study of NiCoCrAlYHfSi bond coatings, the HVOF bond coatings were rougher Ra = 8 μm, closer to commercial HVOF coatings. For TBC coatings on the X4 substrates cycled in air with 10% water vapor, increasing the roughness from Ra = 5 to 8 μm had little effect on the average TBC lifetime. The presence of 10% water vapor reduced the average TBC lifetime for 1483 by 13%, however, in both wet and dry conditions, the lifetimes for this substrate were 30–50% below those observed for X4 substrates. This may be attributed to the lower Al content and higher Ti content in 1483. Roughness and residual stress in the alumina scale were measured on specimens without a ceramic top coating, but no effects were observed due to the change in substrate or the addition of water vapor.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Haynes, J.A. and Unocic, K.A. and Lance, M.J. and Pint, B.A.}, year={2013}, month={Dec}, pages={65–70} }
 @article{hoelzer_unocic_sokolov_feng_2013, title={Joining of 14YWT and F82H by friction stir welding}, volume={442}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2013.04.027}, DOI={10.1016/j.jnucmat.2013.04.027}, abstractNote={Friction stir welding was investigated for joining specimens of the ODS 14YWT ferritic alloy together and to an F82H tempered martensitic steel plate. The FSW run was performed using a polycrystalline boron nitride tool and resulted in good bonding between 14YWT/14YWT and 14YWT/F82H. Joints and interfaces were observed by light microscopy and SEM analysis to be narrow in width. The ultra-small grain size of 14YWT increased by a factor up to 4 while that of F82H decreased by a considerable amount in the weld zones. The TEM analysis showed no significant changes in the size of the oxygen-enriched nanoclusters in the weld zone of 14YWT. However, defects such as a wormhole on the advancing side of the weld zone in 14YWT and small pores associated with joints and interfaces were observed in the FSW sample. The hardness measurements from unaffected zone into weld zones showed ∼20% decrease in hardness for 14YWT (from ∼500 VH to ∼380 VH) and ∼100% increase in hardness of F82H (from ∼220 VH to ∼440 VH).}, number={1-3}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Hoelzer, D.T. and Unocic, K.A. and Sokolov, M.A. and Feng, Z.}, year={2013}, month={Nov}, pages={S529–S534} }
 @article{unocic_brady_pint_2013, title={Oxidation Behavior of Alumina-Forming Austenitic Steel}, number={40982}, journal={Conference Proceedings NACE International, CORROSION 2013 Paper}, author={Unocic, K.A. and Brady, M.P. and Pint, B.A.}, year={2013} }
 @article{unocic_pint_2013, title={Oxidation behavior of co-doped NiCrAl alloys in dry and wet air}, volume={237}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2013.07.068}, DOI={10.1016/j.surfcoat.2013.07.068}, abstractNote={Cast NiCrAl alloys with additions of Y, La, Hf and Ti were evaluated at 1100 °C in wet (10 and 50% H2O) and dry air (0% H2O) in order to optimize such dopants for superalloy bond coatings. The results suggest that the typical Y addition in most coatings could be replaced by La. Also, scale adhesion in cyclic testing was improved with the co-addition of Hf with La or Y. Ti was added to investigate its incorporation in coatings on superalloys containing significant Ti additions. Particularly with co-doped alloys, the addition of Ti had little effect on scale adhesion but did reduce the depth of internal oxidation. Water vapor increased spallation, especially for the least adherent alloys, such as Y,Ti-doped NiCrAl. For the co-doped compositions with Hf, water vapor had a limited effect on scale adhesion and on the alumina growth rate in isothermal exposures. In addition to specimen mass change, the extent of internal oxidation and the depletion of β phase in the substrate were evaluated. Analytical transmission electron microscopy showed that Y, La and Hf co-segregated to the alumina scale grain boundaries and formed dopant-rich oxide precipitates in the scale.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Unocic, Kinga A. and Pint, Bruce A.}, year={2013}, month={Dec}, pages={8–15} }
 @article{pint_unocic_2013, title={Pb–Li compatibility issues for DEMO}, volume={442}, ISSN={0022-3115}, url={http://dx.doi.org/10.1016/j.jnucmat.2013.02.007}, DOI={10.1016/j.jnucmat.2013.02.007}, abstractNote={The current dual coolant fusion blanket concept is limited to a ∼475 °C (748 K) wall temperature due to dissolution/redeposition of the FeCr steel in Pb–Li. Higher wall temperatures could be achieved if compatibility issues can be controlled. Isothermal capsule experiments have demonstrated that thin (<50 μm) Al-rich coatings on Gr.92 steel can reduce mass loss in Pb–Li for up to 5000 h at 700 °C (973 K) and that similar coating performance was obtained for coated oxide dispersion strengthened FeCr steels at 700 °C (973 K). Dissimilar material experiments at 700 °C (973 K) suggested a possible reaction between Fe and SiC in Pb–Li that needs to be further studied as it could limit the blanket temperatures.}, number={1-3}, journal={Journal of Nuclear Materials}, publisher={Elsevier BV}, author={Pint, B.A. and Unocic, K.A.}, year={2013}, month={Nov}, pages={S572–S575} }
 @misc{pint_unocic_haynes_2013, title={The Effect of Water Vapor Content and CO2 on TBC Lifetime}, volume={84666}, ISSN={2994-4031 2994-4023}, url={http://dx.doi.org/10.31399/asm.cp.am-epri-2013p0360}, DOI={10.31399/asm.cp.am-epri-2013p0360}, abstractNote={Abstract While the water vapor content of the combustion gas in natural gas-fired land based turbines is ~10%, it can be 20-85% with coal-derived (syngas or H2) fuels or innovative turbine concepts for more efficient carbon capture. Additional concepts envisage working fluids with high CO2 contents to facilitate carbon capture and sequestration. To investigate the effects of changes in the gas composition on thermal barrier coating (TBC) lifetime, furnace cycling tests (1h cycles) were performed in air with 10, 50 and 90 vol.% water vapor and in CO2-10%H2O and compared to prior results in dry air or O2. Two types of TBCs were investigated: (1) diffusion bond coatings (Pt diffusion or simple or Pt-modified aluminide) with commercially vapor-deposited yttria-stabilized zirconia (YSZ) top coatings on second-generation superalloy N5 and N515 substrates and (2) high velocity oxygen fuel (HVOF) sprayed MCrAlYHfSi bond coatings with air-plasma sprayed YSZ top coatings on superalloy X4 or 1483 substrates. In both cases, a 20-50% decrease in coating lifetime was observed with the addition of water vapor for all but the Pt diffusion coatings which were unaffected by the environment. However, the higher water vapor contents in air did not further decrease the coating lifetime. Initial results for similar diffusion bond coatings in CO2-10%H2O do not show a significant decrease in lifetime due to the addition of CO2. Characterization of the failed coating microstructures showed only minor effects of water vapor and CO2 additions that do not appear to account for the observed changes in lifetime. The current 50°-100°C de-rating of syngas-fired turbines is unlikely to be related to the presence of higher water vapor in the exhaust.}, journal={Advances in Materials Technology for Power Plants}, publisher={ASM International}, author={Pint, B. A. and Unocic, K. A. and Haynes, J. A.}, editor={Gandy, D. and Shingledecker, J.Editors}, year={2013}, month={Oct}, pages={360–370} }
 @inproceedings{unocic_leonard_meyer_lance_pint_2012, title={Compatibility of V/Y2O3/V-4Cr-4Ti Coatings with Liquid Flowing Li}, booktitle={Conference Proceedings of High-Temperature Corrosion and Protection of Materials (HTCPM8)}, author={Unocic, K.A. and Leonard, D.N. and Meyer, H.M., III and Lance, M.J. and Pint, B.A.}, year={2012}, month={May} }
 @article{unocic_baggetto_unocic_veith_dudney_more_2012, title={Coupling EELS/EFTEM Imaging with Environmental Fluid Cell Microscopy}, volume={18}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927612007374}, DOI={10.1017/s1431927612007374}, abstractNote={Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, R.R. and Baggetto, L. and Unocic, K.A. and Veith, G.M. and Dudney, N.J. and More, K.L.}, year={2012}, month={Jul}, pages={1104–1105} }
 @article{unocic_essuman_dryepondt_pint_2012, title={Effect of environment on the scale formed on oxide dispersion strengthened FeCrAl at 1050°C and 1100°C}, volume={29}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.3184/096034012X13317275660176}, DOI={10.1179/096034012x13317275660176}, abstractNote={The surface scale formed on specimens of a commercial oxide dispersion strengthened (ODS) FeCrAl alloy (PM2000) exposed for 1 and 500 h at 1050°C in dry O2, Air+10%H2O and Ar+10%H2O consisted of a two-layer α-Al2O3 structure with a columnar grain inner layer and a finer grain outer layer. The alumina scales formed in Air+10%H2O and Ar+10%H2O were slightly more than half of the thickness of the scale formed in dry O2. The same two-layer structure was also observed after exposure for 500 h at 1100°C in dry O2 and 50%CO2+50%H2O. The alumina scales formed in both atmospheres were similar in thickness. Oxides rich in Y and Ti at the gas – scale interface grew in size and number with time in each case. Using analytical transmission electron microscopy, alumina grain boundary segregation of both Y and Ti was evident near the gas interface but only Y segregation was detected near the metal interface. This difference was attributed to Ti depletion in the adjacent metal and the rapid outward flux of the smaller Ti ion through the scale.}, number={3}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Unocic, K.A. and Essuman, E. and Dryepondt, S. and Pint, B.A.}, year={2012}, month={Sep}, pages={171–180} }
 @article{dryepondt_unocic_pint_2012, title={Effect of exposure in steam or argon on the creep properties of Ni‐based alloys}, volume={63}, ISSN={0947-5117 1521-4176}, url={http://dx.doi.org/10.1002/maco.201206694}, DOI={10.1002/maco.201206694}, abstractNote={Abstract Although expensive, Ni‐based superalloys are of interest for the ultrasupercritical steam program because of their good creep and oxidation resistance at temperatures above 700 °C. As the effect of steam oxidation on the alloy mechanical properties is unknown, creep specimens of alloy CCA617, 740, and 230 were pre‐oxidized for 2000 and 4000 h in steam at 800 °C before testing in air at the same temperature. Compared with as fabricated material, exposure in steam decreased the creep properties of alloy CCA617, had less of an effect on alloy 740, and did not affect alloy 230. Testing of a specimen repolished after steam exposure as well as microstructural observations indicate that the oxidation affected zone at the specimen surface is not responsible for the properties degradation. Surprisingly, a similar time anneal in an inert environment resulted in a drastic decrease of creep rupture life and an increase in the creep rate and elongation at rupture. Transmission electron microscopy analysis revealed that the mechanical properties decrease for alloy CCA617 is related to the absence of γ′ precipitates within the grains.}, number={10}, journal={Materials and Corrosion}, publisher={Wiley}, author={Dryepondt, S. and Unocic, K. A. and Pint, B. A.}, year={2012}, month={Sep}, pages={889–895} }
 @article{haynes_unocic_pint_2013, title={Effect of water vapor on the 1100°C oxidation behavior of plasma-sprayed TBCs with HVOF NiCoCrAlX bond coatings}, volume={215}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2012.07.099}, DOI={10.1016/j.surfcoat.2012.07.099}, abstractNote={With the goal of investigating the reported detrimental effect of water vapor on thermal barrier coating (TBC) performance, furnace cycle experiments were conducted in dry O2 and air with 10 and 50% water vapor at 1100 °C. The TBC systems evaluated were air plasma-sprayed (APS), yttria-stabilized zirconia (YSZ) top coatings with high velocity oxy fuel (HVOF)-deposited NiCoCrAlY or NiCoCrAlYHfSi bond coating. Average TBC lifetime was reduced by ~ 30% in air with 10% water vapor compared to cycling in dry O2, using 1 h cycle durations. Superalloy substrates with Y and La additions also were investigated but showed no statistical change in the average TBC lifetime compared to the base CMSX4 superalloy. In all cases, the bond coating with Hf and Si additions increased YSZ lifetime by 20% or more. Experiments that increased water vapor to 50% showed no further decrease in TBC lifetime. Increasing the cycle frequency to 100 h resulted in a large increase in TBC lifetime, especially for the NiCoCrAlYHfSi bond coatings. Co-doping the NiCoCrAl bond coat with Y and Hf was beneficial to TBC lifetime, but did not mitigate the detrimental impact of water vapor.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Haynes, J.A. and Unocic, K.A. and Pint, B.A.}, year={2013}, month={Jan}, pages={39–45} }
 @article{unocic_pint_2013, title={Effect of water vapor on thermally grown alumina scales on bond coatings}, volume={215}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2012.08.100}, DOI={10.1016/j.surfcoat.2012.08.100}, abstractNote={The role of water vapor on thermal barrier coating (TBC) performance has been investigated for both Pt-modified aluminide and Pt-diffusion bond coatings by characterizing the alumina scale after exposures at 1150 °C. For both types of bond coatings, the average oxide scale thickness formed in dry O2 at 1150 °C was lower than that formed in wet air, especially for air + 10%H2O. In all cases, the average thickness was higher beneath the yttria-stabilized zirconia (YSZ) top coat. Characterization of the alumina scale formed without a YSZ top coat showed differences in morphology and Hf- and Ta-rich oxide precipitates at the gas interface depending on the environment. With and without water vapor, the β-(Ni,Pt)Al coatings showed a martensitic structure with 10–50 nm α-Cr(Re) precipitates. Alumina grain boundary segregation of Y and Hf from the superalloy substrate was easier to detect for the Pt-diffusion coatings.}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Unocic, K.A. and Pint, B.A.}, year={2013}, month={Jan}, pages={30–38} }
 @article{pint_unocic_2012, title={Ionic segregation on grain boundaries in thermally grown alumina scales}, volume={29}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.3184/096034012X13343209167745}, DOI={10.1179/096034012x13343209167745}, abstractNote={This study first examined segregation behaviour in the alumina scale formed after 100 h at 1100°C on bare and MCrAlYHfSi-coated single-crystal superalloys with ~10 ppma La and Y. For the bare superalloy, Hf and Ti were detected on the grain boundaries of the inner columnar alumina layer. Increasing the oxidation temperature to 1200°C for 2 h did not change the segregation behaviour. With the bond coating, both Y and Hf were segregated to the grain boundaries as expected. However, there was evidence of Ti-rich oxide particles near the gas interface suggesting that Ti diffused from the superalloy through the coating. To further understand these segregation observations with multiple dopants, other alumina-forming systems were examined. Alumina scale grain boundary co-segregation of Ti with Y is common for FeCrAl alloys. Co-segregation of Hf and Ti was observed in the scale formed on co-doped NiAl. No La segregation was detected in the scale formed on NiCrAl with only a 19 ppma La addition, however, the scale was adherent.}, number={3}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Pint, Bruce A. and Unocic, Kinga A.}, year={2012}, month={Sep}, pages={257–263} }
 @article{pint_walker_unocic_2012, title={Material compatibility with isothermal Pb–Li}, volume={29}, ISSN={0960-3409 1878-6413}, url={http://dx.doi.org/10.3184/096034012x13334529777329}, DOI={10.3184/096034012x13334529777329}, abstractNote={AbstractEutectic Pb –Li is a leading candidate for current fusion blanket concepts as a coolant. However, there is very little data about the compatibility of most materials with Pb–Li above 500°C where the dissolution rate of many conventional alloys increases rapidly. Current work is beginning to assess Pb–Li compatibility from 500 to 800°C using isothermal capsule experiments. Aluminide coatings hold some promise in protecting conventional Fe-base alloys at 600 – 700°C. However, there is a significant initial Al loss that has not been clearly explained. Furthermore, the reaction product with coated materials is LiAlO2 rather than Al2O3 at 600° and 700°C. Even when pre-oxidized to form α-Al2O3, an alumina layer on FeCrAl transformed to LiAlO2 at 700° and 800°C. At 500°C, the preformed oxide partially transformed from alumina and some Li was detected in the oxide layer.Keywords: Pb–Li compatibilityaluminide coating}, number={2}, journal={Materials at High Temperatures}, publisher={Informa UK Limited}, author={Pint, Bruce A. and Walker, Larry R. and Unocic, Kinga A.}, year={2012}, month={Jun}, pages={129–135} }
 @article{hoelzer_unocic_coffey_feng_2012, title={Microstructural Characterization of Friction Stir Welded Oxide Dispersion Strengthened 14YWT Ferritic Alloy and F82H Tempered Martensitic Steel}, volume={18}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927612010148}, DOI={10.1017/s1431927612010148}, abstractNote={Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Hoelzer, D.T. and Unocic, K.A. and Coffey, D.W. and Feng, Z.}, year={2012}, month={Jul}, pages={1658–1659} }
 @article{unocic_pint_2012, title={Microstructure and Chemistry of the Oxide Scale and Pt-containing Coatings Deposited on Superalloy N5}, volume={18}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927612010239}, DOI={10.1017/s1431927612010239}, abstractNote={Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, K.A. and Pint, B.A.}, year={2012}, month={Jul}, pages={1676–1677} }
 @article{rother_keiser_brady_unocic_anovitz_littrell_peascoe-meisner_santella_wesolowski_cole_2012, title={Small-angle neutron scattering study of the wet and dry high-temperature oxidation of alumina- and chromia-forming stainless steels}, volume={58}, ISSN={0010-938X}, url={http://dx.doi.org/10.1016/j.corsci.2012.01.024}, DOI={10.1016/j.corsci.2012.01.024}, abstractNote={Foils of T347 and an alumina-forming austenitic (AFA) stainless steel were oxidized at 800 °C in dry air, air with 10% H2O, and air with 10% D2O. Significant changes in the small angle neutron scattering (SANS) signal were observed for the T347 stainless steel as a function of oxidation time in dry air whereas the AFA alloy showed no significant scattering changes resulting from oxidation. For both alloys, similar scattering was observed in dry and wet air (H2O and D2O) exposure, indicating that watervapour did not result in significant H/D retention or induce significant morphological changes in the oxide scales.}, journal={Corrosion Science}, publisher={Elsevier BV}, author={Rother, G. and Keiser, J.R. and Brady, M.P. and Unocic, K.A. and Anovitz, L.M. and Littrell, K.C. and Peascoe-Meisner, R.A. and Santella, M.L. and Wesolowski, D.J. and Cole, D.R.}, year={2012}, month={May}, pages={121–132} }
 @article{lydon_unocic_bae_jones_nair_2012, title={Structure–Property Relationships of Inorganically Surface-Modified Zeolite Molecular Sieves for Nanocomposite Membrane Fabrication}, volume={116}, ISSN={1932-7447 1932-7455}, url={http://dx.doi.org/10.1021/jp301497d}, DOI={10.1021/jp301497d}, abstractNote={A multiscale experimental study of the structural, compositional, and morphological characteristics of aluminosilicate (LTA) and pure-silica (MFI) zeolite materials surface-modified with MgOxHy nanostructures is presented. These characteristics are correlated with the suitability of such materials in the fabrication of LTA/Matrimid mixed-matrix membranes (MMMs) for CO2/CH4 separations. The four functionalization methods studied in this work produce surface nanostructures that may appear superficially similar under SEM observation but in fact differ considerably in shape, size, surface coverage, surface area/roughness, degree of attachment to the zeolite surface, and degree of zeolite pore blocking. The evaluation of these characteristics by a combination of TEM, HRTEM, N2 physisorption, multiscale compositional analysis (XPS, EDX, and ICP-AES elemental analysis), and diffraction (ED and XRD) allows improved understanding of the origin of disparate gas permeation properties observed in MMMs made with four types of surface-modified zeolite LTA materials, as well as a rational selection of the method expected to result in the best enhancement of the desired properties (in the present case, CO2/CH4 selectivity increase without sacrificing permeability). A method based on ion exchange of the LTA with Mg2+, followed by base-induced precipitation and growth of MgOxHy nanostructures, deemed "ion exchange functionalization" here, offers modified particles with the best overall characteristics resulting in the most effective MMMs. LTA/Matrimid MMMs containing ion exchange functionalized particles had a considerably higher CO2/CH4 selectivity (∼40) than could be obtained with the other functionalization techniques (∼30), while maintaining a CO2 permeability of ∼10 barrers. A parallel study on pure silica MFI surface nanostructures is also presented to compare and contrast with the zeolite LTA case.}, number={17}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society (ACS)}, author={Lydon, Megan E. and Unocic, Kinga A. and Bae, Tae-Hyun and Jones, Christopher W. and Nair, Sankar}, year={2012}, month={Apr}, pages={9636–9645} }
 @misc{pint_haynes_unocic_zhang_2012, title={The Effect of Water Vapor and Superalloy Composition on Thermal Barrier Coating Lifetime}, url={http://dx.doi.org/10.7449/2012/superalloys_2012_723_732}, DOI={10.7449/2012/superalloys_2012_723_732}, abstractNote={New power generation concepts may contain higher water vapor in the turbine combustion gas due to the fuel or to steam dilution.To assess the effect of higher water vapor content on thermal barrier coating performance, furnace cycle (1h) testing was conducted in air with 10, 50 and 90 vol.% water vapor and compared to prior results in dry O 2 .The first series of experiments examined Pt diffusion (γ+γ') and Pt-modified aluminide (β) bond coatings on second-generation superalloy N5 at 1150°C with commercially vapor-deposited yttria-stabilized zirconia (YSZ) top coats.Compared to dry O 2 , the average coating lifetimes with Pt diffusion coatings were unaffected by the addition of water vapor while the Pt-modified aluminide coating average lifetime was reduced by >50% with 10% water vapor, but less reduction was observed with higher water contents.A similar set of coatings on low Re superalloy N515 showed no debit in lifetime with Pt aluminide bond coatings exposed to 10% water vapor.Characterization of the alumina scale thickness at failure showed a thicker oxide beneath the YSZ coating (compared to the scale without a top coating) for both types of bond coatings, and an increase in the oxide thickness with the addition of 10% water vapor.These observations were further studied using analytical transmission electron microscopy.The second series of experiments examined high velocity oxygen fuel (HVOF) MCrAlY and MCrAlYHfSi bond coatings and air-plasma sprayed YSZ top coatings on X4 superalloy substrates with and without Y and La additions.Compared to a dry O 2 baseline, the addition of 10% water vapor decreased the YSZ coating lifetime for either bond coating by ~30% at 1100°C.Substrates with Y and La additions showed no change in the average lifetime in 10% water vapor compared to standard X4.A further increase to 50% water vapor did not further decrease the average lifetime of one group of coatings.To better simulate base-load power generation, one group of specimens was cycled with 100h cycles, which substantially increased the coating lifetime.In each case, higher average lifetimes were observed with Hf in the bond coating.Initial characterization of the alumina scales formed at failure showed little effect of the water vapor addition, bond coating composition or substrate composition.For both series of coatings, the addition of 10% water vapor to the experiment reduced YSZ coating lifetime.However, increasing to 50% or 90% H 2 O showed no additional decrease in average YSZ lifetime.}, journal={Superalloys 2012 (Twelfth International Symposium)}, publisher={John Wiley & Sons, Inc.}, author={Pint, B. and Haynes, J. and Unocic, K. and Zhang, Y.}, year={2012}, pages={723–732} }
 @misc{unocic_unocic_pint_lipschutz_2011, title={Characterization of Pre- and Post-Service Grain Boundary Phases in a Cast Austenitic Steel}, url={http://dx.doi.org/10.1115/gt2011-46710}, DOI={10.1115/gt2011-46710}, abstractNote={Austenitic steel castings are currently being used in components for industrial gas turbine engines. Service experience has indicated a degradation of mechanical properties with extended exposures at elevated temperature. The purpose of this study was to characterize the grain boundary phases that develop during the casting processes as a likely explanation for the observed performance. In order to isolate these precipitates, a variety of electron microscopy characterization techniques were used to characterize their composition after various heat treatments and service exposure. In the baseline, as-cast and annealed condition, a discontinuous network of grain boundary metal carbides was observed. These precipitates coarsened during short-term annealing at 649°C and a denuded zone formed in the adjacent matrix. When the 38,600 h service-exposed material was analyzed, the grain boundaries were highly decorated with a more continuous film of grain boundary carbides as well as voids attributed to creep cavitation. In addition to carbides, acicular AlN precipitates were identified on the grain boundaries of the casting examined after service exposure.}, journal={Volume 4: Cycle Innovations; Fans and Blowers; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine; Oil and Gas Applications}, publisher={ASMEDC}, author={Unocic, Raymond R. and Unocic, Kinga A. and Pint, Bruce A. and Lipschutz, Mark D.}, year={2011}, month={Jan}, pages={755–760} }
 @article{unocic_parish_pint_2011, title={Characterization of the alumina scale formed on coated and uncoated doped superalloys}, volume={206}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2011.07.044}, DOI={10.1016/j.surfcoat.2011.07.044}, abstractNote={To investigate the mechanisms by which Y and La dopants affect the oxidation behavior of Ni-base single‐crystal superalloys, the oxide scales formed on two variants of a commercial X4 alloy, each with and without a MCrAlYHfSi coating were characterized. The alloy systems were oxidized for 100 h at 1100 °C and then examined using analytical transmission electron microscopy. Without a coating, a duplex scale was formed on the superalloy surface comprised of an outer Ni‐rich spinel‐type layer and an inner columnar α‐Al2O3 layer. In this case, Hf and Ti were found segregated to the alumina grain boundaries in the outer part of the scale on both alloys but only Hf was detected near the metal–alumina interface. There was no evidence of Ta, Y or La segregation to the alumina scale grain boundaries after this exposure. The scale formed on the alloys with the thermally sprayed coating was primarily alumina, and Y and Hf segregated to the alumina grain boundaries for both alloys. There was evidence of Ti-rich oxides in the outer part of the scale indicating that Ti had diffused through the coating into the thermally grown oxide but La was not found.}, number={7}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Unocic, K.A. and Parish, C.M. and Pint, B.A.}, year={2011}, month={Dec}, pages={1522–1528} }
 @misc{pint_brady_yamamoto_unocic_matthews_2011, title={Evaluation of Commercial Alumina-Forming Austenitic Foil for Advanced Recuperators}, url={http://dx.doi.org/10.1115/gt2011-46704}, DOI={10.1115/gt2011-46704}, abstractNote={A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced recuperator applications. This fully austenitic alloy is optimized for creep strength while allowing the formation of a chemically-stable external alumina scale at temperatures up to 900°C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. The first batch of commercially fabricated foil was produced with a composition selected from prior laboratory creep and oxidation results. The results for ∼80 and ∼105μm thick foil are compared to the prior laboratory-fabricated foils and other commercial candidates. Results from initial creep testing at 750°C show comparable creep strength to other commercial Fe-base foil candidates. Laboratory exposures in humid air at 650°–800°C have shown excellent oxidation resistance for this composition. Similar oxidation resistance was observed for sheet specimens of the first set of alloys exposed in a modified 65kW microturbine for up to 6,000h.}, journal={Volume 3: Controls, Diagnostics and Instrumentation; Education; Electric Power; Microturbines and Small Turbomachinery; Solar Brayton and Rankine Cycle}, publisher={ASMEDC}, author={Pint, Bruce A. and Brady, Michael P. and Yamamoto, Yukinori and Unocic, Kinga A. and Matthews, Wendy J.}, year={2011}, month={Jan}, pages={971–976} }
 @article{brady_unocic_lance_santella_yamamoto_walker_2011, title={Increasing the Upper Temperature Oxidation Limit of Alumina Forming Austenitic Stainless Steels in Air with Water Vapor}, volume={75}, ISSN={0030-770X 1573-4889}, url={http://dx.doi.org/10.1007/s11085-011-9237-7}, DOI={10.1007/s11085-011-9237-7}, number={5-6}, journal={Oxidation of Metals}, publisher={Springer Science and Business Media LLC}, author={Brady, M. P. and Unocic, K. A. and Lance, M. J. and Santella, M. L. and Yamamoto, Y. and Walker, L. R.}, year={2011}, month={Feb}, pages={337–357} }
 @article{wade_coffey_ghosh_wittig_kang_allard_unocic_davidson_tolk_2012, title={Nanostructure TEM analysis of diamond cold cathode field emitters}, volume={22}, ISSN={0925-9635}, url={http://dx.doi.org/10.1016/j.diamond.2011.11.007}, DOI={10.1016/j.diamond.2011.11.007}, abstractNote={Diamond cold-cathode devices have demonstrated significant potential as electron field emitters. Ultra-sharp diamond pyramidal tips (~ 5 nm tip radius) have been fabricated, and show improvement in emission when compared to conventional field emitters. However, the emission mechanisms in these complex diamond nanostructures are not well understood. Transmission electron microscopy performed in this study provides new insight into tip structure and composition with implications for field emission and diamond growth.}, journal={Diamond and Related Materials}, publisher={Elsevier BV}, author={Wade, Travis C. and Coffey, Dorothy W. and Ghosh, Nikkon and Wittig, James E. and Kang, Weng P. and Allard, Lawrence F. and Unocic, Kinga A. and Davidson, Jimmy L. and Tolk, Norman H.}, year={2012}, month={Feb}, pages={29–32} }
 @inproceedings{vande put_unocic_pint_brady_2011, title={Performance of Alumina-Forming Austenitic Steels, Fe-base and Ni-base alloys exposed to metal dusting environments}, booktitle={Conference Proceedings NACE Corrosion 2011 Conference and Expo}, author={Vande Put, A. and Unocic, K.A. and Pint, B.A. and Brady, M.P.}, year={2011}, month={Mar} }
 @inproceedings{dryepondt_unocic_vande put_2011, title={Qualification of New, Commercial ODS Alloys}, booktitle={Annual Conference on Fossil Energy Materials Conference Proceedings}, author={Dryepondt, S. and Unocic, K.A. and Vande Put, A.}, year={2011}, month={May} }
 @inproceedings{pint_unocic_dryepond_maziasz_santella_2011, title={Revival of Interest in Super-Bainitic Steels for Energy Applications}, booktitle={Conference Proceedings Welding and Fabrication Technology for New Power Plants and Components: Second International EPRI Conference}, author={Pint, B.A. and Unocic, K.A. and Dryepond, S. and Maziasz, P.J. and Santella, M.L.}, year={2011}, month={Jun} }
 @article{seyeux_frankel_missert_unocic_klein_galtayries_marcus_2011, title={ToF-SIMS Imaging Study of the Early Stages of Corrosion in Al-Cu Thin Films}, volume={158}, ISSN={0013-4651}, url={http://dx.doi.org/10.1149/1.3568944}, DOI={10.1149/1.3568944}, abstractNote={The pitting corrosion of Al-Cu thin film alloys was investigated using samples that were heat treated in air to form through-thickness Al2Cu particles within an Al-0.5% Cu matrix. Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) analysis revealed Cu-rich regions 250–800 nm in lateral extent near the metal/oxide interface. Following exposure that generated pitting corrosion, secondary electron, secondary ion, and AFM images showed pits with size and density similar to those of the Cu-rich regions. The role of the Cu-rich regions is addressed.}, number={6}, journal={Journal of The Electrochemical Society}, publisher={The Electrochemical Society}, author={Seyeux, A. and Frankel, G. S. and Missert, N. and Unocic, K. A. and Klein, L. H. and Galtayries, A. and Marcus, P.}, year={2011}, pages={C165} }
 @inproceedings{unocic_daehn_unocic_mills_hayes_2010, title={A TEM Study of Creep Deformation Mechanisms in Allvac 718Plus®}, url={http://dx.doi.org/10.7449/2010/superalloys_2010_607_615}, DOI={10.7449/2010/superalloys_2010_607_615}, abstractNote={A preliminary study on the evolution of creep deformation substructure in Ni-base superalloy Allvac 718Plus has been performed.Specimens crept at 620 MPa and at temperatures ranging from 690-732ºC were examined utilizing diffraction contrast TEM characterization techniques.Creep was interrupted at 1-2.5% strain in order to study the deformation substructure following a limited amount of deformation.The dominant deformation modes at each of the test temperatures were highly planar in nature and involved shearing of the matrix and ′ precipitates on {111} glide planes.In addition, paired a/2<110> dislocations were evident which suggest an antiphase boundary shearing mechanism.Creep induced microtwinning was also observed at the highest creep temperature which was created by identical a/6<112> Shockley partial dislocations that shear the matrix and ′ precipitates on consecutive close packed {111} glide planes.}, booktitle={7th International Symposium on Superalloy 718 and Derivatives (2010)}, publisher={John Wiley & Sons, Inc.}, author={Unocic, R. and Daehn, G. and Unocic, K. and Mills, M. and Hayes, R.}, year={2010}, pages={607–615} }
 @inproceedings{unocic_pint_wright_2010, title={Characterization of Reaction Products from Field Exposed Tubes}, booktitle={EPRI 6th International Conference on Advances in Materials Technology for Fossil Power Plants}, author={Unocic, K.A. and Pint, B.A. and Wright, I.G.}, year={2010}, month={Aug} }
 @article{unocic_pint_2010, title={Characterization of the alumina scale formed on a commercial MCrAlYHfSi coating}, volume={205}, ISSN={0257-8972}, url={http://dx.doi.org/10.1016/j.surfcoat.2010.08.111}, DOI={10.1016/j.surfcoat.2010.08.111}, abstractNote={A commercial NiCoCrAlYHfSi coating deposited on a Ni-base superalloy substrate was characterized before and after high temperature oxidation. The combination of Y, Hf and Si additions is reported to improve coating performance. Advanced characterization techniques including scanning-transmission electron microscopy were used to study the segregation behavior of Y and Hf ions to the alumina grain boundaries after 200 h at 1050 °C and 100 and 200 h exposures at 1100 °C. After both exposure times, two distinct oxide layers were observed. The outer transient layer included many Y- and Hf-rich oxide particles. The inner layer consisted of columnar α-Al2O3 grains normal to the surface of the coating. Segregation of Y and Hf ions was found on the alumina grain boundaries as has been observed in model alloys with similar compositions. Isothermal exposures for up to 200 h at 1050° and 1100 °C caused a minimal increase in surface roughness. However, 200 1-h cycles at 1100 °C resulted in a more significant increase in surface roughness.}, number={5}, journal={Surface and Coatings Technology}, publisher={Elsevier BV}, author={Unocic, K.A. and Pint, B.A.}, year={2010}, month={Nov}, pages={1178–1182} }
 @inproceedings{unocic_pint_hayes_unocic_2010, title={Effect of Microstucture and Environment on the High-Temperature Oxidation Behavior of Alloy 718Plus®}, url={http://dx.doi.org/10.7449/2010/superalloys_2010_977_991}, DOI={10.7449/2010/superalloys_2010_977_991}, abstractNote={The effect of microstructure on the oxidation behavior of 718Plus was evaluated in dry air, wet air and steam environments at 650°-700°C.Tests at 800°C were also performed in an attempt to accelerate the testing.Oxidation in wet air simulates turbine combustion environments and causes net mass losses at 650°-700°C because of the volatilization of Cr oxy-hydroxides that is not observed in ambient air testing.At 800°C, mass gains were measured but significant Cr depletion can be measured in the alloy after exposure due to volatilization.Changes in temperature and environment had much larger effects on oxidation performance than the two microstructures evaluated.Advanced characterization techniques were used to compare the differences in the oxide scale formed on alloys with different process conditions.At higher temperatures, the surface oxide was primarily identified as Cr 2 O 3 by x-ray diffraction.Crosssection analysis showed an increase in internal oxidation attack with increasing temperature.The internal attack appeared to be associated with rod-shaped Ni 3 Nb precipitates (δ-phase).Because of the changes in microstructure at 800°C, the steam and wet air evaluations appeared to be less relevant to lower temperatures.Thus, increasing the exposure temperature to 800°C does not appear to be a good strategy for accelerated testing of 718Plus.}, booktitle={7th International Symposium on Superalloy 718 and Derivatives (2010)}, publisher={John Wiley & Sons, Inc.}, author={Unocic, K. and Pint, B. and Hayes, R. and Unocic, R.}, year={2010}, pages={977–991} }
 @article{unocic_mills_daehn_2010, title={Effect of gallium focused ion beam milling on preparation of aluminium thin foils}, volume={240}, ISSN={0022-2720 1365-2818}, url={http://dx.doi.org/10.1111/j.1365-2818.2010.03401.x}, DOI={10.1111/j.1365-2818.2010.03401.x}, abstractNote={Summary Focussed ion beam milling has greatly extended the utility of the atom probe and transmission electron microscope because it enables sample preparation with a level of dimensional control never before possible. Using focussed ion beam it is possible to extract the samples from desired and very specific locations. The artefacts associated with this sample preparation method must also be fully understood. In this work, issues specifically relevant to the focussed ion beam milling of aluminium alloys are presented. After using the focussed ion beam as a sample preparation technique it is evident that gallium will concentrate in three areas of the sample: on the surface, on grain boundaries and at interphase boundaries. This work also shows that low‐energy Ar ion nanomilling is potentially quite effective for removing gallium implantation layers and gallium from the internal surfaces of aluminium thin foils.}, number={3}, journal={Journal of Microscopy}, publisher={Wiley}, author={Unocic, K.A. and Mills, M.J. and Daehn, G.S.}, year={2010}, month={Nov}, pages={227–238} }
 @article{adhikari_unocic_zhai_frankel_zimmerman_fristad_2011, title={Hexafluorozirconic acid based surface pretreatments: Characterization and performance assessment}, volume={56}, ISSN={0013-4686}, url={http://dx.doi.org/10.1016/j.electacta.2010.07.037}, DOI={10.1016/j.electacta.2010.07.037}, abstractNote={A new phosphate-free pretreatment from Henkel Corp. named TecTalis®, was investigated. The treatment bath is composed of dilute hexafluorozirconic acid with small quantities of non-hazardous components containing Si and Cu. The corrosion resistance of treated steel was compared to samples treated in a phosphate conversion coating bath, in simple hexafluorozirconic acid and in TecTalis without the addition of the Cu-containing component. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to characterize the coating surface morphology, structure and composition. A Quartz Crystal Microbalance (QCM) was used for studying film growth kinetics on thin films of pure Fe, Al and Zn. Electrochemical Impedance Spectroscopy (EIS) was performed on treated and painted steel for studying long-term corrosion performance of the coatings. The phosphate-free coating provided long-term corrosion performance comparable to that of phosphate conversion coatings. The coatings uniformly cover the surface in the form of 10–20 nm sized nodules and clusters of these features up to 500 nm in size. The coatings are usually about 20–30 nm thick and are mostly composed of Zr and O with enrichment of copper at randomly distributed locations and clusters.}, number={4}, journal={Electrochimica Acta}, publisher={Elsevier BV}, author={Adhikari, Saikat and Unocic, K.A. and Zhai, Y. and Frankel, G.S. and Zimmerman, John and Fristad, W.}, year={2011}, month={Jan}, pages={1912–1924} }
 @misc{pint_unocic_dryepondt_2010, title={Oxidation of Superalloys in Extreme Environments}, url={http://dx.doi.org/10.7449/2010/superalloys_2010_861_875}, DOI={10.7449/2010/superalloys_2010_861_875}, abstractNote={With the current interest in increased efficiency and reduced emissions, materials in power generation systems are increasingly exposed to more aggressive environments and higher temperatures.It is important to understand how these environments can increase corrosion rates, possibly reducing performance and likely shortening component lifetimes.Superalloys like 718 and its derivatives primarily rely on the formation of an external Cr-rich oxide layer or scale for environmental protection at typical application temperatures (≤700°C).While many laboratory oxidation and creep experiments are conducted in ambient air, the application environment for these alloys often involves combustion products, such as H 2 O and CO-CO 2 .The effect of these environments is not completely understood, especially the impact of long-term exposures, typically required of superalloy components in turbines.Air and fuel impurities, especially S and Na, can result in accelerated degradation such as the well known hot corrosion attack.While the effect of environment on crack growth has been studied, less information is available on the effect of environment on creep and fatigue properties.Initial work is being conducted to better understand the role of environment on creep properties, eventually including in-situ testing.Examples are given from steam and wet air environments and comparisons of different superalloy compositions with cast versus wrought microstructures.}, journal={7th International Symposium on Superalloy 718 and Derivatives (2010)}, publisher={John Wiley & Sons, Inc.}, author={Pint, B. and Unocic, K. and Dryepondt, S.}, year={2010}, pages={861–875} }
 @inproceedings{sabau_wright_zhang_pint_unocic_2010, title={Temperature Evolution and Oxide Growth in Water Wall Tubes of Supercritical Unit}, booktitle={Boiler Tube and HRSG Tube Failures and Inspections International Conference}, author={Sabau, A.S. and Wright, I.G. and Zhang, W. and Pint, B.A. and Unocic, K.A.}, year={2010}, month={Apr} }
 @article{unocic_hayes_mills_daehn_2009, title={Microstructural Features Leading to Enhanced Resistance to Grain Boundary Creep Cracking in ALLVAC 718Plus}, volume={41}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/s11661-009-0099-4}, DOI={10.1007/s11661-009-0099-4}, number={2}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Unocic, Kinga A. and Hayes, Robert W. and Mills, Michael J. and Daehn, Glenn S.}, year={2009}, month={Nov}, pages={409–420} }
 @article{unocic_mills_daehn_2008, title={Challenges in Preparing Aluminum Alloys for Grain Boundary Characterization}, volume={14}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927608082305}, DOI={10.1017/s1431927608082305}, abstractNote={Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008}, number={S2}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, KA and Mills, MJ and Daehn, GS}, year={2008}, month={Aug}, pages={556–557} }
 @article{unocic_daehn_2008, title={Jacquet-Lucas Award: TEM sample preparation method for grain boundary phase identification in Al-Mg alloys.}, volume={166}, number={2}, journal={Advanced Materials & Processes}, author={Unocic, K.A. and Daehn, G.S.}, year={2008}, month={Feb}, pages={42–43} }
 @article{unocic_kobe_mills_daehn_2006, title={Grain Boundary Precipitate Modification for Improved Intergranular Corrosion Resistance}, volume={519-521}, ISSN={1662-9752}, url={http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.327}, DOI={10.4028/www.scientific.net/msf.519-521.327}, abstractNote={Intergranular corrosion is a significant concern for Al-Mg alloys when subjected to a corrosive salt-water environment. To address this issue, the standard composition of a 5XXX series aluminum alloy (AA5083) was modified in an attempt to improve the alloy’s overall corrosion resistance through alloying and thermal processing. The concept being that through alloying and heat treatments, desirable precipitate phases such as τ- and/or τ-copper rich phase(s) that are known to offer corrosion resistance would potentially form that could effectively improve intergranular corrosion behavior. Therefore, the chemical composition of standard AA5083 was modified by adding various amounts of copper and zinc. Sensitization heat treatments were then performed to determine the specific conditions under which these phases would form. LOM, SEM, STEM imaging and conventional TEM were used to analyze microstructural features. Corrosion was attributed to a network of detrimental Mg-rich grain boundary precipitates in the standard alloy. Alloying with Cu and Zn can offer improved intergranular corrosion behavior. The mechanism seems to be either by delaying or eliminating precipitation at the grain boundaries.}, journal={Materials Science Forum}, publisher={Trans Tech Publications, Ltd.}, author={Unocic, Kinga A. and Kobe, Paul and Mills, Michael J. and Daehn, Glenn S.}, year={2006}, month={Jul}, pages={327–332} }
 @article{unocic_mills_daehn_kobe_2005, title={Microstructural Analysis of 5XXX Series Aluminum Alloys  for Optimal Strength and Corrosion Resistance}, volume={11}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/s1431927605508158}, DOI={10.1017/s1431927605508158}, abstractNote={Extract HTML view is not available for this content. However, as you have access to this content, a full PDF is available via the 'Save PDF' action button. Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005}, number={S02}, journal={Microscopy and Microanalysis}, publisher={Oxford University Press (OUP)}, author={Unocic, K and Mills, M and Daehn, G and Kobe, P}, year={2005}, month={Aug} }
 @inproceedings{claves_janiszewska_misiolek_libura_2004, title={Metal Flow in Billets of Thin-Walled Extrudates}, booktitle={8th International Aluminum Extrusion Technology Seminar ET 2004}, publisher={The Aluminum Association & Aluminum Extruders Council}, author={Claves, S.R. and Janiszewska, K.A. and Misiolek, W.Z. and Libura, W.}, year={2004}, pages={55–67} }