Microstructure, mechanical properties and ablation behavior of ultra-high-temperature Ta-Hf-C solid solution coating prepared by a step-by-step plasma solid solution method

Ultra-high-temperature Ta-Hf-C solid solution coating is successfully prepared by induction plasma spheroidization (IPS) combine with vacuum plasma spraying (VPS). The microstructure, mechanical properties and ablation performance of the Ta-Hf-C coating are investigated. Results show that the as-sprayed coating is a solid solution Ta-Hf-C ternary ceramic coating. The highest average hardness and elastic modulus obtained by nanoindentation are 28.05 GPa and 307.35 GPa, respectively. The coating exhibits a good ablation resistance under heat flux of 4.18 MW/m(2). After 30 s ablation, the mass and linear ablation rates of the Ta-Hf-C coating are -0.58 mg/s and -0.94 mu m/s, respectively. The ablation resistance mechanism is studied. The formation of Hf6Ta2O17 on the coating surface and the Ta-Hf-C-O intermediate transition layer in the coating slow down the ablation and improve the ability to resist ultra-high temperature.