Effect of the Al₂O₃ additive on the high temperature ablation behavior of the ZrC–ZrO₂ coating for SiC-coated carbon/carbon composites

The Al₂O₃ additive content in the ZrC–ZrO₂ composite coating is adjusted by using the supersonic atmosphere plasma spraying method and the coatings are then tested by the oxyacetylene torch. The influence of the Al₂O₃ additive content on the anti-ablation property is studied. Results show that the ZrC–ZrO₂ coating containing 10 vol% Al₂O₃ owns the lowest surface porosity and the best ablation resistance property. The ablated area is compact and mainly consists of big grains, which is because the addition of Al₂O₃ can promote the sintering of liquid ZrO₂. The formed Al–Zr–O structure can promote the completeness and stability of the ZrO₂ scale, which can inhibit the penetration of oxygen.