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.