Effect of Monolithic LaB6 on the Ablation Resistance of ZrC/SiC Coating Prepared by Supersonic Plasma Spraying for C/C Composites

Ablation resistance of monolithic LaB6-doped ZrC coating for SiC-coated carbon/carbon composites by supersonic atmospheric plasma spray was investigated under an oxyacetylene torch with a heat flux of 4.18 MW/m(2). Result shows that ZrC coating with 10 vol.% LaB6 has a good ablation resistance compared with pure ZrC, ZrC with 20 vol.% LaB6 and SiC-doped ZrC coating. After ablation for 15 s, the weight is increased by 1.12 mg/s. The good ablation resistance is ascribed to the formation of a stabilized scale which consists of protective La2Zr2O7-containing molten phase and ZrO2 particles keeping the integrity of the coating. Copyright (C) 2016, The editorial office of Journal of Materials Science & Technology. Published by Elsevier Limited.