Ultra-high temperature ceramic TaB₂-TaC-SiC coating for oxidation protection of SiC-coated carbon/carbon composites

In order to improve the oxidation resistance of the TaB₂-SiC based coating applied on carbon/carbon (C/C) composites, TaC phase was in-situ introduced and a TaB₂-TaC-SiC ultra-high temperature ceramics (UHTCs) coating was prepared on the surface of SiC coated C/C composites by in-situ synthesis method. The results showed that the outer coating consists of smooth non-angular TaB₂ phase, regular hexagonal prism shape TaC phase and SiC phase, which are synchronously obtained during the preparation of the coating. The multilayer coating could protect the C/C composites against oxidation for 400 h at 1773 K in air with only 1.43% weight loss. A double self-healing oxidation layers (inner SiO₂ glass layer and outer compound Ta-Si-O silicate glass layer) formed on the surface of the coating provides a dual oxidation protection for the coating, which was responsible for the excellent oxidation resistance.