Fabrication of dense (Hf, Ta)C thermal protection coating on Ta10W alloy by dual plasma solid solution effects for higher ablation resistance above 2200 °C

Enhancing the ablation resistance of ultra-high temperature ceramics based on the solid-liquid theory has become a research hotspot in the field of thermal protection. In this study, HfC-TaC micron composite powders were prepared using spray granulation, and a solid-solution (Hf, Ta)C coating was deposited on the Ta10W substrate through the dual solid-solution effect of radio frequency inductively coupled plasma spheroidization and supersonic atmospheric plasma spraying. The phase composition, microstructure, ablation resistance, and underlying mechanisms of the coating were investigated. The results indicate that after ablation for 200 s at 2200 °C and 2300 °C, the high melting point solid-phase products, HfO 2 and Hf 6 Ta 2 O 17 , serve as structural skeletons, while the liquid-phase Ta 2 O 5 acts as a filler, collectively protecting the Ta10W substrate from oxidation and ablation.