@article{jia_ajayi_xu_2020, title={Dielectric properties of polymer-derived ceramic reinforced with boron nitride nanotubes}, volume={103}, ISSN={["1551-2916"]}, DOI={10.1111/jace.17301}, abstractNote={Abstract}, number={10}, journal={JOURNAL OF THE AMERICAN CERAMIC SOCIETY}, author={Jia, Yujun and Ajayi, Tosin D. and Xu, Chengying}, year={2020}, month={Sep}, pages={5731–5742} }
 @article{jia_ajayi_wahls_ramakrishnan_ekkad_xu_2020, title={Multifunctional Ceramic Composite System for Simultaneous Thermal Protection and Electromagnetic Interference Shielding for Carbon Fiber-Reinforced Polymer Composites}, volume={12}, ISSN={1944-8244 1944-8252}, url={http://dx.doi.org/10.1021/acsami.0c17361}, DOI={10.1021/acsami.0c17361}, abstractNote={Achieving a high electrical conductivity while maintaining a good thermal insulation is often contradictory in the material design for the goal of simultaneous thermal protection and electromagnetic interference shielding. The reason is that materials with a high electrical conductivity often pertain a high thermal conductivity. To address this challenge, this study reports a multifunctional ceramic composite system for carbon fiber-reinforced polymer composites. The fabricated multifunctional ceramic composite system has a multilayer structure. The polymer-derived SiCN ceramic reinforced with yttria-stabilized zirconia fibers serves as the thermal protection and impedance-matching layer, while the yttria-stabilized zirconia fiber-reinforced SiCN ceramic with carbon nanotubes provides the electromagnetic interference shielding. The thermal conductance of the multilayered ceramic composite is about 22.5% lower compared to that of the carbon fiber-reinforced polymer composites. The thermal insulation test during the steady-state condition shows that the hybrid composite can be used up to 300 °C while keeping the temperature reaching the surface of carbon fiber-reinforced polymer composites at around 167.8 °C. The flame test was used to characterize the thermal protection capability under transient conditions. The hybrid composite showed temperature differences of 72.9 and 280.7 °C during the low- and high-temperature settings, respectively. The average total shielding efficiency per thickness of the fabricated four-layered ceramic composite system was 21.45 dB/mm, which showed a high reflection-dominant electromagnetic interference shielding. The average total shielding efficiency per thickness of the eight-layered composite system was 16.57 dB/mm, revealing a high absorption-dominant electromagnetic interference shielding. Typical carbon fiber-reinforced polymer composites reveal a reflection-dominant electromagnetic interference shielding. The electrons can freely move in the percolated carbon nanotubes within the inner layers of the composite material, which provide the improved electromagnetic interference shielding ability. The movement of electrons was impeded by the top and bottom layers whose thermal conduction relies on the lattice vibrations, resulting in a satisfactory thermal insulation of the composite materials and impedance matching with the free space. Results of this study showed that materials with a good thermal insulation and electromagnetic interference shielding can be obtained simultaneously by confining the electron movement inside the materials and refraining their movement at the skin surface.}, number={52}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Jia, Yujun and Ajayi, Tosin D. and Wahls, Benjamin H. and Ramakrishnan, Kishore Ranganath and Ekkad, Srinath and Xu, Chengying}, year={2020}, month={Dec}, pages={58005–58017} }
 @article{jia_ajayi_roberts_chung_xu_2020, title={Ultrahigh-Temperature Ceramic-Polymer-Derived SiOC Ceramic Composites for High-Performance Electromagnetic Interference Shielding}, volume={12}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.0c08479}, abstractNote={High-performance electromagnetic interference (EMI) shielding materials for high-temperature harsh environment are highly required for electronics and aerospace applications. Here, a composite made of ultra-high temperature ceramic and polymer derived SiOC ceramic (PDC-SiOC) with high EMI shielding was reported for such applications. A total EMI shielding efficiency (SET) of 26.67 dB with a thickness of 0.6 mm at Ka-band (26.5-40 GHz) was reported for ZrB2 fabricated by spark plasma sintering, which showed reflection dominant shielding. A unique interface of t-ZrO2 was formed after the introduction of PDC-SiOC into ZrB2. This interface has better electrical conductivity than SiOC. The composites also displayed reflection dominant shielding. Accordingly, the composite with a normalized ZrB2 fraction of 50 % pyrolyzed at 1000 °C exhibited significantly SET of 72 dB (over 99.99999 % shielded) with a thickness of 3 mm at the entire Ka-band. A maximum SET of 90.8 dB (over 99.9999999 % shielded) was achieved with a thickness of 3 mm at around 39.7 GHz.}, number={41}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Jia, Yujun and Ajayi, Tosin D. and Roberts, Mark A., Jr. and Chung, Ching-Chang and Xu, Chengying}, year={2020}, month={Oct}, pages={46254–46266} }
 @article{jia_ajayi_morales_chowdhury_sauti_chu_park_xu_2019, title={Thermal properties of polymer-derived ceramic reinforced with boron nitride nanotubes}, volume={102}, ISSN={["1551-2916"]}, DOI={10.1111/jace.16670}, abstractNote={Abstract}, number={12}, journal={JOURNAL OF THE AMERICAN CERAMIC SOCIETY}, author={Jia, Yujun and Ajayi, Tosin D. and Morales, Justin and Chowdhury, Md Atiqur Rahman and Sauti, Godfrey and Chu, Sang-Hyon and Park, Cheol and Xu, Chengying}, year={2019}, month={Dec}, pages={7584–7593} }