Ablation behavior of (Zr,Ta)B2-SiC coating on carbon/carbon composites at 2300 °C

Abstract Zr-Ta-B-SiC multiphase coating was prepared on carbon/carbon composites by pack cementation and slurry method. The (Zr,Ta)B2 solid solution was found to be the key antiablative component. The ablation behavior suggested that the synthesized Zr0.70Ta0.30B2-SiC coating exhibited the best ablation resistance at 2300 °C. It is asserted that the micromorphology and distribution of Zr-Ta-O in the coating played a vital role in the evolution of the protective layer and ablation performance. A coating with ∼30 % Ta was beneficial for stabilizing the t-ZrO2 phase and alleviating the volume change at high temperature. The formation of a thermal barrier and low volatility of Zr-Ta-O layer were responsible for the excellent ablation resistance.