Laser ablation behaviors of vacuum plasma sprayed ZrC-based coatings

ZrC, ZrC-30vol% SiC, and ZrC-30vol% TiC coatings were fabricated by vacuum plasma spray and the laser ablation behaviors were evaluated by a CO2 laser beam under two heat fluxes (15.9 and 25.5MW/m(2)). The phase compositions and microstructures of the coatings after ablation were investigated and the effect of SiC and TiC additives was analyzed. The results showed that the ZrC-SiC coating displayed better ablation resistance compared with the ZrC and ZrC-TiC coatings under 15.9MW/m(2) heat flux. While the ZrC-TiC coating exhibited the improved ablation resistance under 25.5MW/m(2) heat flux. The continuous and integral ZrO2-SiO2 scale provided protective effect for the ZrC-SiC coating. A liquid ZrO2-TiO2 layer which owned self-healing ability was formed for the ZrC-TiC coating in both heat fluxes. However, the state of the formed liquid, like amount, viscosity, evaporation, and decomposition, was influenced by the environment and was vital for the ablation resistance. This work might give a clue for designing ultrahigh-temperature ceramics as potential laser ablation-resistant coating materials.