A Novel ZrC – YB ₆ ‐Modified PCS Coating Chopped Carbon Fiber/Boron Phenolic Ceramizable Composite Exhibited Outstanding High‐Temperature Resistance

Carbon fiber/phenolic resin composites are commonly employed as ablation heat‐resistant materials in aerospace applications. However, their susceptibility to oxidative degradation and high ablation rates severely limit their development. Therefore, through a synergistic strategy combining fiber coating and matrix modification, a ceramizable resin‐based thermal protection material containing a polycarbosilane (PCS) coating and ZrC–YB 6 was prepared. The research revealed that the ceramizable composite exhibited a bending strength as high as 41.82 MPa after static ablation at 1400°C in an oxygen‐rich environment. Concurrently, after 30 s of ablation under a 4.2 MW/m 2 oxygen‐acetylene heat flux, its linear ablation rate was reduced to 0.006 mm/s, respectively. Through microstructural analysis, phase analysis, and thermodynamic calculations, the ablation mechanism was elucidated. Pyc and ceramic products such as ZrO 2 , ZrB 2 , YSZ, SiC, and SiO 2 form a composite structure of ceramic–glass–pyrolytic carbon on the ablation surface, significantly enhancing the composite's resistance to oxidation corrosion.