Failure behavior of SiC/SiC with BSAS-based EBC in gas combustion environment

To promote the application of SiC/SiC in hot-end components in aero-engines, the thermal shock behavior of SiC/SiC and SiC/SiC-EBC were investigated in gas combustion environment between 450 ˚C and 1200 ˚C. The tensile strength change, microstructure evolution and thermal cycling performance of samples after 200, 400, 1000 and 2000 cycles were studied respectively to reveal the damage and failure mechanism. Cracking damage induced by thermal stress was the main reason for performance degradation of SiC/SiC after initial thermal cycles, then oxidation/corrosion damage dominated with increasing cycles. The oxidation/corrosion damage to SiC/SiC was effectively inhibited by EBC with almost no reduction in strength. However, the poor crack resistance of SiC/SiC was the main factor affecting its thermal shock performance. Improving the crack resistance or self-healing ability of SiC/SiC and combining it with EBC is considered to be an effective strategy to increase its service lifetime.