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, ZrB2-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 mu m/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 SiO2 prevents inner coating from ablation and the chemical erosion becomes the leading mechanism.