Ablation response behavior and mechanism of (Hf, Ta)B2-(Hf, Ta)C-SiC ultra-high temperature multi-phase ceramics

Aiming at forming a stable ablation layer for hafnium-based ultrahigh-temperature ceramics under ablation environment, in this work, the Ta-based ceramic was introduced into the Hf-based ceramic, and the effect of Hf/Ta molar ratios on the ablation response behavior and mechanism of (Hf, Ta)B 2 -(Hf, Ta)C-SiC ceramics was investigated. It was found that the introduction of Ta could form a continuous and dense ablation layer. When Hf/Ta= 0.9:0.1, the ceramic composite presented excellent ablation resistance, and the linear ablation rate was −0.083 μm/s, which was only 5.85 % of that of Hf-based ceramics (HfB 2 -HfC-SiC). The excellent ablation resistance attributed to that the ablation products (Ta 2 O 5 and Hf 6 Ta 2 O 17 ) could strongly bonded to the substrate, which was conducive to enhance the stability of the ablation layer.