Ablation resistance of HfC-SiC coating prepared by supersonic atmospheric plasma spraying for SiC-coated C/C composites

In order to improve the ablation properties of carbon/carbon composites, HfC-SiC coating was deposited on the surface of SiC-coated C/C composites by supersonic atmospheric plasma spraying. The morphology and microstructure of HfC-SiC coating were characterized by SEM and XRD. The ablation resistance test was carried out by oxyacetylene torch. The results show that the structure of coating is dense and the as-prepared HfC-SiC coating can protect the C/C composites against ablation. After ablation for 30 s, the linear ablation rate and mass ablation rate of the coating are −0.44 μm/s and 0.18 mg/s, respectively. In the ablation center region, a Hf-Si-O compound oxide layer is generated on the surface of HfC-SiC coating, which is conducive to protecting the C/C composites from ablation. With the ablation time increasing to 60 s, the linear ablation rate and mass ablation rate are changed to −0.38 μm/s and 0.26 mg/s, respectively. Meanwhile, the thickness of the outer Hf-Si-O compound layer also increases.