Ablation behaviors of ZrC-TiC coatings prepared by vacuum plasma spray: Above 2000 degrees C

摘要

ZrC-TiC coatings were fabricated by vacuum plasma spray and their ablation resistance were evaluated and compared with ZrC-SiC coating by a plasma flame with a heat flux of 4.02 MW/m(2). The microstructure and phase compositions of the as-sprayed and ablated coatings were characterized and the function of TiC addition on the ablation resistance was investigated. The results showed that the ablation resistance of the ZrC-TiC coating was much better than that of the ZrC-SiC coating under the present ablation conditions. The decrease of surface temperatures with the increasing of TiC content were observed. (Zr, Ti)O-2 eutectic phase in liquid state was observed. The low vapor and decomposition pressures of TiO2, combined with the formation of (Zr, Ti)O-2 liquid contributed to the excellent ablation resistance of the ZrC-TiC coating. This work affirmed that TiC could be an ideal addition to improve the ablation resistance of the ZrC coating in harsh environment above 2000 degrees C.