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 x 10(-7) m/s and 6.78 x 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.