• Coatings (Cr, Ti, and/or Zr) on SiC were corroded in LWR water to test corrosion . • Combinatorial and Trilayer physical vapor deposited coatings were LWR water tested. • Combinatorial coatings performed better than trilayer samples during corrosion. • Higher chromium content shows potential for better corrosion resistance . • Low hardness measurements predicted which coatings would spall. The simulated boiling water condition corrosion properties of multilayer and combinatorial physical vapor deposition metal coatings (Zr, Cr, and/or Ti) deposited on a SiC f -SiC composite were investigated. Various compositions within the ternary system were corroded to the most suitable composition preventing underlying SiC f -SiC from further attack. Mass measurements and visual observations were conducted to identify which coatings formed protective oxides and which coatings spalled. Transmission electron microscopy was conducted to observe the microstructure of the physical vapor deposition metal layer before and after corrosion as well as identify the oxide which were forming.