Ablation resistance of HfC-TaC-Hf₆Ta₂O₁₇ composite coatings prepared by vacuum plasma spraying

HfC-TaC-Hf6Ta2O17 composite coatings are successfully prepared by vacuum plasma spraying. The microstruc-ture and forming mechanism of the coating are investigated. As a melt adhesive, Hf6Ta2O17 reduces the porosity of composite coatings. After the ablation assessment under heat flux of 4.18 MW/m(2), the HT10 coating (80 vol% HfC-10 vol% TaC-10 vol% Hf6Ta2O17) shows the best ablation performance (-0.4 mu m/s,-0.5 mg/s). Hf6Ta2O17 can effectively prevent the formation of low melting point Ta-O phase from damaging the structural integrity of the oxide layer. The acquisition of Hf6Ta2O17 oxidation products occupies a more critical position in the enhancement of anti-ablation performance of Ta-Hf-C coating.