TaB2-SiC-Si multiphase oxidation protective coating for SiC-coated carbon/carbon composites

摘要

To mprove the oxidation resistance of the carbon/carbon (C/C) composites, a TaB2-SiC-Si multiphase oxidation protective ceramic coating was pivnared on the surface of SiC coated C/C composites by pack cementation. Results showed that the outer multiphase coating was mainly composed of TB_2, SiC and Si. The multilayer coating is about 200 |xm in thickness, which has no penetration crack or big hole. The coating could protect C/C from oxidation for 300 h with only 0.26 x 10~(-2) g~2/cm~2 mass loss at 1773 K in air. The formed silicate glass layer containing SiO_2 and tantalum oxides can not only seal the defects in the coating, but also reduce oxygen diffusion rates, thus improving the oxidation resistance.