1999 Volume 48 Issue 9Appendix Pages 163-168
Refractory silicon-based barrier coatings are a promising approach for improving the environmental durability of C/C composites in severe environment such as high temperature oxidation atmosphere. The oxidation resistance of C/C composites coated with a newly developed multi-layer C-Si (composite with SiC fiber)-SiC (CVI) was investigated. The C-Si interleaving layer between C/C composite substrate and SiC coating is expected to act as a buffer layer that reduced the thermal stress caused by the mismatching of the coefficient of thermal expansions (CTEs) between the substrate and the coating. The multi-layer coated 3-D C/C sample exhibited significantly improved oxidation resistance owing to change the crack propagation (such as the crack termination and deflection) of the CVD-SiC coating when compared to that without C-Si interleaf. The coated specimens were examined by oxidation test at 1700°C in the methane-fired exhaust gas.
