Ablation behavior and mechanisms of ZrC-SiC-MoSi2 coated C/C-SiC-ZrC ceramic matrix composites under oxyacetylene torch

To further improve the anti-ablation property of C/C composites in different ablation environments, ZrC-SiC-MoSi2 coatings containing 34 wt.% and 60 wt.% Zr were prepared on C/C-SiC-ZrC ceramic matrix composites via slurry painting (SP) method. And the ablation behavior of the coated composites was investigated in oxyacetylene torch environment with three kinds of fluxes of oxygen and acetylene. The results show that with the increase of Zr content, the particle sizes of ZrC and SiC in the coatings are significantly reduced, with the particles distributing more homogeneously. The linear ablation rates of the coatings with 60 wt.% Zr increase with the increase of oxygen and acetylene fluxes, while for the coatings with 34 wt.% Zr, the linear ablation rates increase at the beginning and then decrease. The ablation mechanisms of the coatings under different conditions were discussed as well. With the increase of oxygen and acetylene fluxes, main ablation mechanisms change from oxidation to oxidation plus evaporation and then to the combination of oxidation, evaporation and denudation.