Multiple ablation resistance of La₂O₃/Y₂O₃-doped C/SiC–ZrC composites

In this contribution, La₂O₃ or Y₂O₃ was added to C/SiC–ZrC composites in order to improve their multiple ablation properties. Ablation results showed that the La₂O₃-doped C/SiC–ZrC composites could withstand three times ablation under the oxyacetylene torch flame, while the Y₂O₃-doped C/SiC–ZrC composites were severely damaged after twice. The exposure time for each ablation test was 30 s. The formation of a dense La₂Zr₂O₇ protective layer during ablation enhanced the resistance to further ablation. However, as for the Y₂O₃-doped C/SiC–ZrC, the Y₂O₃ neither reacted with silica to reduce its violation nor dissolved into zirconia to suppress its phase transformation, resulting in no obvious improvement in the ablation resistance.