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. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.