Ablation mechanism of WC-SiC double layer coating under oxyacetylene torch test

A WC-SiC double-layer coating was prepared on C/C composites to improve their anti-ablation property. The WC outer layer was designed to withstand high heat flux by its high mechanical strength, the SiC inner layer could transform into SiO2 to block oxygen by its good anti-oxygen permeability. During ablation process, amounts of SiO2 filled into the pores and cracks of WC outer layer, forming a steadily self-filling and cooling structure. As a result, the mass and linear ablation rates of WC-SiC coated C/C composites were 0.013 mg s−1 cm2 and −1.61 µm/s, respectively. Compared with single SiC coated and single WC coated C/C composites, the linear ablation rates decreased by 46.3% and 27.3%, respectively, indicating that WC-SiC coating has a remarkable effect to resist chemical and mechanical ablation.