Improving the ablation resistance of SiC ceramics in high-enthalpy plasma flow: Inhibition of oxidation layer loss via TiB₂ addition

This study systematically investigates the ablation behavior of TiB₂–SiC multiphase ceramics under high-enthalpy, non-equilibrium plasma flows using a high-frequency plasma wind tunnel. The results indicate that a 1 mol% addition of TiB₂ to SiC ceramics results in the best ablation resistance. In high-temperature environments containing dissociated oxygen, TiB₂ oxidizes to form TiO₂ and B₂O₃. At the gas–solid interface, B₂O₃ and TiO₂ further promote the oxidation of volatile SiO to SiO₂, which subsequently redeposits onto the oxide layer. This process suppresses degradation of the surface oxide layer, thereby delaying exposure of underlying ceramic matrix to the plasma flow and consequently enhancing its ablation resistance. These findings provide valuable insights for the design of SiC-based thermal protection materials capable of long-term operation under high-enthalpy plasma flows.