The dominant factor of C/SiC composites in ablation environment with heat and particle flow.

As thermal structure components in scramjet engines, carbon-reinforced silicon carbide (C/SiC) composites are often subject to an ablation coupled with heat and particle flows. This study simulates the working environment of the scramjet engine's thermal structure component by coupling an Al 2 O 3 particle flow with a plasma flow. The ablation behaviour of C/SiC composites in the presence and absence of particle impact have been comprehensively analysed. The results show that the factor dominating the ablation behaviour varies with temperature. At relatively low temperatures, the particles have difficulty breaking down the dense SiO 2 layer formed from the oxidation of SiC in the presence of heat flow which is the dominant factor. As the temperature rises, the SiC begins to shift towards active oxidation. A few defects appear in the oxide layer, leading to a significant particle mechanical flaking effect. Particle flow is the dominant factor. However, a higher temperature led to the substantial active oxidation of SiC, and the oxide layer dissipated, exposing more defects. The heat flow causes a strong oxidation reaction, and the scouring effect of the particles is significant as well, both of which play a dominant role in the ablation process. • At lower ablation temperatures, SiC forms a dense oxide layer, with heat flow predominantly governing the ablation process. • As temperature rises, SiC undergoes active oxidation, resulting in defects within the oxide layer, where particle flow controls the ablation process. • At higher temperatures, both heat flow and particle flow jointly govern the ablation process. [ABSTRACT FROM AUTHOR]