Cyclic ablation mechanisms of Cr₂AlC ceramics in nitrogen plasma flame at 1600 ℃

Cr₂AlC, as a ternary layered MAX phase ceramic with excellent oxidation resistance and ablation resistance, has great potential in thermal protection materials. To further tap its potential as a recyclable thermal protection material in extreme environment, the cyclic ablation performance of Cr₂AlC under nitrogen plasma flame at 1600 ℃ was systematically studied in this paper. During the cycles (each lasting three minutes) of ablation, Cr₂AlC maintained structural integrity and exhibited low linear and mass ablation rates. After three cycles of ablation, the linear ablation rate and mass ablation rate were 0.050 µm/s and 0.048 mg/s, respectively. The analysis of surface and near-surface components shows that Al₈Cr₅ produced by the decomposition of Cr₂AlC is the origin of the excellent ablation performance of Cr₂AlC ceramics. However, as the cycle time and total ablation time increase, Cr₂AlC and Al₈Cr₅ near the surface will be depleted under high-temperature oxidation, leading to material failure. This study presents the excellent cycling and long-term ablation properties of Cr₂AlC ceramics, revealing their enormous application prospects in reproducible thermal protection materials.