Ablation resistance and heat insulation performance of integrated C_f/SiBCN ceramic-polymer gradient composites in arc wind tunnel

The advancement of future hypersonic vehicles poses tangible challenges to the innovation of thermal protection materials. Herein, we prepared a novel integrated C_f/SiBCN amorphous ceramic-polymer continuous gradient thermal protection composite. Ablation tests were conducted on the integrated gradient material specimens using an arc-heated wind tunnel under heat flux conditions of 1.85 MW/m²and 2.15 MW/m², respectively. Although the ablation surface temperature of the material reached 1915 °C, its back temperature remained much lower than 105 °C within 300 s. The mass ablation rate and linear ablation rate were 3.42 × 10⁻⁶ g/(mm²·s) and −0.0028 mm/s, respectively. No obvious ablation cracks or holes were observed on the material surface. Notably, an in-situ molten protective layer formed on the specimen surface during the ablation process. Composed of silicides and borides, this dense molten layer covering the surface not only enables self-repair of damage but also enhances the ablation resistance and oxidation resistance of the material further. This material exhibits excellent ablation resistance, thermal insulation performance, and ablation deformation resistance. This study contributes to advancing the innovation of functionally and structurally integrated gradient thermal protection materials and has practical application potential in the field of hypersonic vehicles.