A Novel ZrC–YB6-Modified PCS Coating Chopped Carbon Fiber/Boron Phenolic Ceramizable Composite Exhibited Outstanding High-Temperature Resistance

Abstract

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–YB₆ 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/m² 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 ZrO₂, ZrB₂, YSZ, SiC, and SiO₂ form a composite structure of ceramic–glass–pyrolytic carbon on the ablation surface, significantly enhancing the composite's resistance to oxidation corrosion.