Effect of heat flux on ablation behaviour and mechanism of C/C-ZrB₂-SiC composite under oxyacetylene torch flame

The ablation property of C/C-ZrB₂-SiC composite under oxyacetylene torch flame with different heat flux was investigated. The ablation performance decreased with the increase of heat flux from 2400 to 4200kW/m² and the ablation mechanism changed from chemical erosion to mechanical denudation. The good ablation resistance under 2400kW/m² is attributed to the formation of SiO₂-ZrO₂ mixture. When heat flux is 3200kW/m², the formation of ZrO₂ can partly prevent the diffusion of oxygen and provide ablation protection. But with heat flux increasing, the increase of mechanical denudation results in the reduction of ablation performance.