Study on the mechanism of ultra-high temperature ablation of ZrB₂–SiC–TaSi₂ coatings by low-pressure plasma spraying on the C/C composites

To improve the high-temperature oxidation resistance of C/C composites, ZrB₂–SiC (ZS) and ZrB₂–SiC–TaSi₂ (ZST) ultra-high temperature ceramics coatings were prepared on their surfaces using induction plasma spheroidization and low-pressure plasma spraying (LPPS). Ablation behaviors of the ZS and ZST coatings were evaluated at 1800°C, 2000°C, and 2200°C using the oxyacetylene flame, we found that the ZS coatings had good ablation resistance at 1800°C, but rapidly failed at 2000°C. Whereas, the ZST coating always performed good oxidation and ablation resistance at even 2000°C with a mass ablation rate of 4.68 × 10^-5 g/s and a linear ablation rate of -1.63 × 10^-5 mm s^-1. The enhancement of the high temperature ablation resistance property was attributed to the introduction of the TaSi₂, which improved the density of the coatings prepared by LPPS, reduced the volatilization of the glassy phase at high temperature, and enabled ZrO₂ to form a dense oxide layer.