Ablation resistance of ZrB₂-SiC coating prepared by supersonic atmosphere plasma spraying for SiC-coated carbon/carbon composites

To improve the ablation resistance of carbon/carbon (C/C) composites, ZrB₂-SiC coating was prepared on the surface of SiC-coated C/C composites by supersonic atmosphere plasma spraying. Ablation resistance of the coating was investigated by oxyacetylene torch under different heat flux. Results show that the multilayer coating is dense and its thickness is about 60 μm. The mass and linear ablation rates of the coated C/C composites are 0.4×10^-3 g/s and 0.6 μm/s after ablation for 60 s under the heat flux of 2400 kW/m². However, the coating is failure after ablation for 60 s under the heat flux of 4200 kW/m². The good ablation resistance of the coating under the heat flux of 2400 kW/m² is mainly attributed to the formation of a dense ZrO₂-SiO₂ scale, which could act as thermal barrier and reduce inward diffusion of oxygen.