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.