Ablation behavior of ZrB₂-based coating prepared by supersonic plasma spraying for sic-coated C/C composites under oxyacetylene torch

In order to improve the ablation resistance of C/C composites, ZrB ₂-based coating was prepared by supersonic atmosphere plasma spraying for SiC-coated C/C composites. The phase composition, microstructure, and anti-ablation property of the coating were investigated. Results show that the supersonic atmosphere plasma spraying is an effective method to prepare a dense ZrB₂-based coating. The coating largely improves the ablation resistance of C/C composites. The linear ablation rate is 0.17 μm/s after ablation for 60 s in oxyacetylene torch. In ablation center, the ablation performance is determined by complicated mechanical denudation and chemical erosion. The formation of ZrO₂ during ablation can partly prevent the diffusion of oxygen, which contributes to the good ablation resistance of ZrB₂-based coating. In transition zone, the generation of SiO ₂ prevents inner coating from ablation and the chemical erosion becomes the leading mechanism.