Ablation behavior of a novel carbonitrides HfC_0.68N_0.32 coating for C/C composites in laser and oxyacetylene environment

A HfC_0.68N_0.32 solid solution coating was synthesized on the surface of C/C composites by chemical vapor deposition (CVD). The mechanical properties and ablation resistance of HfC_0.68N_0.32 coating were investigated under laser and oxyacetylene conditions. Results indicated that HfC_0.68N_0.32 coating exhibited higher hardness and elastic modulus than HfC and HfN coatings. The phase separation of HfC_0.68N_0.32 coating generated in the laser ablation environment with power of 800 W, and the mass ablation rate was 0.17 mg/s after ablation for 10 s. Furthermore, the surface temperature of the coated sample reached 2600 ℃ under an oxyacetylene environment with a heat flux density of 4.2 MW/m², resulting mass and linear ablation rates of 0.34 mg/s and 0.23 µm/s respectively after ablation for 100 s, showing a great potential in the field of ultra-high temperature ablation protection.