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

Abstract In this contribution, La 2 O 3 or Y 2 O 3 was added to C/SiC–ZrC composites in order to improve their multiple ablation properties. Ablation results showed that the La 2 O 3 -doped C/SiC–ZrC composites could withstand three times ablation under the oxyacetylene torch flame, while the Y 2 O 3 -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 La 2 Zr 2 O 7 protective layer during ablation enhanced the resistance to further ablation. However, as for the Y 2 O 3 -doped C/SiC–ZrC, the Y 2 O 3 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.