Corrosion behavior of LSI-based 3D needled C/SiC composites subjected to burner rig test

The C/SiC composites prepared by liquid silicon infiltration(LSI) were tested on a burner rig at approximately 1400 °C with flame velocity of 30–50 m/s. The microstructural morphologies before and after tests are analyzed to propose corrosion mechanisms. The corrosion behavior of C/SiC under high-temperature and high-velocity flame conditions is divided intofollow three stages which are repeated during whole tests: (1) removal of carbon fiber and pyrolytic carbon on surface; (2) shedding of matrix on the surface; (3) shedding of chopped fiber web layers. Moreover, the melt and volatilization of SiO2 which is the oxidation product of SiC, and the thermal stress induced fracture under high-temperature and high-velocity flame impacting are proposed as main mechanisms of the SiC matrix shedding.