Design of ablation resistant Zr-Ta-O-C composite coating for service above 2400 ℃

To improve the limited ablation resistance of Zr-Ta-O compound film induced by Ta continuous enrichment, phase diagram design and ablation tests (4.2 MW/m²) were conducted to obtain an appropriate modification strategy. The Zr₆Ta₂O₁₇ intermediate phase was synthesized and introduced into plasma sprayed ZrC coatings. Compared with ZrC coating, the linear variation rate of ZrC-5 vol% Zr₆Ta₂O₁₇ coating was decreased by 80%. The greatly improved ablation performance was attributed to the weakening effect of minor Ta solid solution on the Zr-O covalent bond and appropriate addition amount of Zr₆Ta₂O₁₇ phase to keep Ta/Zr molar ratio under a low level (Ta/Zr < 1/11).