WSi₂ modified HfB₂-SiC coating: Microstructure and ablation resistance

To enhance the ablation resistance of carbon/carbon composites, WSi₂ modified HfB₂-SiC coating was prepared by slurry dipping combined with vapor silicon infiltration. The effect of WSi₂ contents on the ablation performance of the coating was investigated. The results showed that the coating with 20 wt% WSi₂ had the best ablation resistance under oxyacetylene torch. During ablation, a dense Hf-Si-W-O oxide layer was covered on the coating surface, inhibiting the diffusion of oxygen. Additionally, WSi₂ with high emissivity and the formed W with good thermal conductivity played a role in reducing the ablation temperature. These effects contributed to the improvement of ablation performance.