RESEARCH ON MoSi_2-BASED OXIDATION PROTECTIVE COATING FOR SiC-COATED CARBON/CARBON COMPOSITES PREPARED BY SUPERSONIC PLASMA SPRAYING

摘要

In order to improve the oxidation protective ability of the SiC-coated (C/C) composites, a MoSi_2-based coating was prepared on them by a novel supersonic plasma spraying method. Microstructures of the coating were analyzed by XRD and SEM. XRD result indicates the MoSi_2-based coating is primarily composed of MoSi_2, Mo_sSi_3 and SiO_2. SEM analyses show that the MoSi_2-based coating is dense and crack-free, and has a good interface bonding with the SiC-coated C/C composites. Oxidation test shows that the coating has excellent oxidation and thermal shock resistance, and can effectively protect C/C composites from oxidation at 1673K in air for more than 500h and endure the thermal cycle between 1673K and room temperature for 15 times. The outstanding oxidation protective ability mainly attributes to the formation of SiO_2 film on the surface of the coating.