Microstructure and corrosion behavior of in-situ grown Y3Si2C2 coated SiC fibers exposed to air and wet-oxygen at 1400 ℃

Y 3 Si 2 C 2 ternary ceramics were in-situ grown on the third-generation Chinese commercial SiC fiber (KD-SA SiC fiber) surface via molten salt method. Microstructures and oxidation/corrosion behavior of in-situ grown Y 3 Si 2 C 2 coated SiC fibers exposed to air and wet-oxygen at 1400 ℃ were investigated. Results indicated that the layered Y 3 Si 2 C 2 slices with thickness of approximately 15 nm can be successfully in-situ grown on SiC fibers. The product on the fibers surface after oxidation/corrosion at 1400 ℃ for 1 h in both ambient air and wet-oxygen are Y 2 Si 2 O 7 and SiO 2 . Moreover, microstructural characterization indicates that the immigration and expansion of gaseous bubbles induced by oxidation product, mainly CO, result in microstructural differences of SiC fiber specimens, and finally oxidation mechanism based on the microstructural difference were proposed.