Efficient fabrication of light C/C-SiHfCB composites with excellent thermal shock resistance and high temperature ablation resistance above 2000℃

To meet the stringent demands for toughening and ablation resistance in high-speed aircraft components, C/C-SiHfCB composites were fabricated by introducing a novel liquid SiHfCB precursor into a porous C/C matrix via high-pressure precursor infiltration and pyrolysis. This approach yielded an integrated three-dimensional continuous ceramic phase tightly bonded to the matrix. The composite achieved a flexural strength of 237 ± 42 MPa with non-brittle fracture, a critical thermal shock temperature difference of 912℃. During oxyacetylene flame tests, extremely low linear ablation rates of 5.7 × 10⁻⁴ mm/s and 15.6 × 10⁻⁴ mm/s were recorded at 2000℃ and 2150℃, respectively. An effective oxygen diffusion barrier consisting of an HfO₂ skeleton with SiO₂-filled pores was formed. This study offers a viable strategy for the synergistic optimization of mechanical and ablation properties.