Formation of C_f/C Composites with SiC Concentration Gradient on the Surface by SHCLD Technique

Abstract

Adopting two-step deposition processes, SiC concentration gradient layer on the surface of Cf/C composites were prepared via Self-heating Chemical Liquid Deposition (SHRCLD) technique. In second deposition process, carbon and SiC were codepositted from pure kerosene and TEOS. The temperature of deposition was 1000°C~1200°C and the system pressure was 0.1MPa. Different thickness of gradient layers would be attained via adjusting the proportion of TEOS in procurer and controlling deposition time. Oxidation resistance, and mechanical tests were investigated, and the microstructure was observed under SEM. Results showed that the flexural strength of the composites was 123.7 MPa. The antioxidation temperature of Cf/C composites with the gradient layer is up to 800°C in air. The process of SHCLD technique is simple and easy to be controlled, and the deposition rate is faster than other conventional technique.