An oxidation and ablation protective WSi₂-HfB₂-SiC coating for SiC coated C/C composites at 1973 K and above

WSi₂-HfB₂-SiC outer coatings were prepared by in-situ sintering reaction methods. The effect of WSi₂ content on the oxidation resistance of HfB₂-SiC coating was investigated. The results show that the WSi₂-HfB₂-SiC coating with 25 wt.% WSi₂ (W2) has the best oxidation resistance and can protect C/C substrate for 100 h at 1973 K in air environment. After ablation for 90 s, the linear ablation rate and mass ablation rate of W2 are −3.89 × 10⁻⁷ m/s and 6.78 × 10^-5 g/s, respectively, showing excellent ablation resistance. The good oxidation and ablation resistance of W2 is attributed to the formation of flowing multiphase glass with inlay.