Ablation behavior of ZrC-La₂O₃ coating for SiC-coated carbon/carbon composites under an oxyacetylene torch

To improve the ablation resistance of carbon/carbon (C/C) composites, ZrC-La₂O₃ coating was prepared on SiC-coated C/C composites by supersonic atmosphere plasma spraying. Ablation resistance of the coating was evaluated under an oxyacetylene torch with a heat flux of 4.2 MW/m². The coating shows a significant improvement on the ablation resistance compared with monophase ZrC coating and ZrC coating with LaB₆. The good ablation resistance of the coating is mainly attributed to the formation of dense and high-viscosity scale surface which is beneficial to reducing the infiltration of oxygen and resisting the scouring from the flame during ablation. The positive effect of La₂O₃ is to improve the compactness of the scale surface during ablation.