Ablation behavior of ZrC-SiHfOC-MoSi₂ coating for carbon/carbon composites under Ar-O₂ plasma flame

To improve ablation resistance of ZrC-SiMOC-based (M = transition metal) coatings, a ZrC-SiHfOC-MoSi₂ coating was investigated. The results showed that the MoSi₂ shell limits the decomposition of SiC under SAPS and decreases pores of the coating. ZrC-SiHfOC coating showed large-area peeling after an Ar-O₂ plasma flame ablation for 90 s. In contrast, ZrC-SiHfOC-MoSi₂ coating revealed low ablation rates after ablation for 360 s, with the mass and linear ablation rates of −0.05 mg/s and 0.14 μm/s, respectively. MoSi₂ provides rich SiO₂ to form ZrSiO₄ to reduce the damage by plasma flame, thereby improving the ablation resistance of ZrC-based coatings.