Degradation of CVD-SiC coated PIP-C/SiC composites exposed to the hot firing test based on MMH/N2O4 bipropellants

Ablation property of CVD-SiC coated PIP-C/SiC composites was investigated by using a hot-firing test in a liquid propellant rocket motor. The effect of the combustion temperature was studied; then ablation mechanisms of coated composites were discussed. The degradation of PIP-C/SiC composites was determined by analyzing surface variations. Two different ablation modes of C/SiC composites were discussed. The coupling effects (thermal–mechanical denudation and thermal–chemical erosion) worsened the degradation of the coated PIP-C/SiC composites. CVD-SiC coating provided better protection for the composites under the MMH/N2O4 bipropellants tests.