A Si-Mo-Cr OXIDATION PROTECTIVE COATING FOR C/SiC COATED CARBON/CARBON COMPOSITES

摘要

To protect carbon/carbon(C/C) composites from oxidation, a novel Si-Mo-Cr alloy oxidation protective coating has been produced by pack cementation. The phase composition and microstructure of the as-prepared coatings were characterized by XRD, SEM and EDS analyses. XRD result indicates the Si-Mo-Cr external layer was primarily composed of SiC, MoSi_2, CrSi_2 and residual Si. Oxidation test shows that, the as-prepared coating characterized by excellent oxidation resistance and thermal shock resistance could effectively protect C/C composites from oxidation at 1773K in air for 186h and endure the thermal cycle between 1773K and room temperature for 9 times, and the corresponding weight loss is only 0.33%. The slight weight loss is mainly attributed to the formation of microcracks on the coating surface.