Degradation of Cf-SiC composites under hypersonic conditions

Abstract

Carbon based composites particularly C_f-SiC composites are finding wide range of applications at elevated temperature. A number of component of hypersonic vehicles are made from these composites. In view of these, C_f-SiC composites fabricated by liquid silicon impregnation (LSI) and isothermal chemical vapor impregnation (ICVI) are exposed to hypersonic condition with the help of an induction plasma based erosion test facility. Mass loss of exposed samples was determined by semi-micro balance. Degraded surfaces were examined with the help of scanning electron microscopy. Pyrocarbon/silicon carbide [(PyC/SiC) n; n = 4] coated C_f-SiC composites fabricated by ICVI technique exhibits the best performance. The main materials removal mechanism is estimated to be mechanical erosion and ablation of investigated material.