Enhanced ablation resistance and mechanical properties of CMP/C-HfC composites contributed by dual-skeleton reinforcement and coating protection

Abstract

High-thermal-conductivity mesophase pitch-based carbon fiber reinforced carbon (HTC-C_MP/C) composites encounter severe challenges with intrinsic oxidation and thermal ablation at ultra-high temperature, thus enhancing their thermal protection performance is crucial for stable operation. In this study, a dual-skeleton reinforced C_MP/C-HfC composites were fabricated via reactive melt infiltration, and the ZrC/SiC@C_MP/C-HfC composites were simultaneously prepared based on a coating-matrix integration strategy. The results show that the prepared C_MP/C-HfC composites exhibit flexural strengths of ${\sigma }_{0.5}$ = 169.03 MPa and ${\sigma }_{1.0}$ = 247.15 MPa, representing 52.8 % and 63.04 % improvements over C_MP/C composites, respectively. The mass ablation rate and linear ablation rate are 0.367 mg s⁻¹ and -1.167 μm s⁻¹, showing 86.1 % and 107.5 % reductions compared to C_MP/C composites. Moreover, the ZrC/SiC coating further effectively mitigates ablation-induced powdering and spalling in C_MP/C-HfC composites while enhancing both thermal conductivity and flexural mechanical properties. This balanced enhancement of mechanical-thermal-ablative protection performances relies on the synergistic effects of the dual-skeleton structure combining continuous HfC framework and HTC-C_MP/C skeleton, and effective thermal protection of the coating system. This work provides novel insights and valuable references for thermal protection design in C_MP/C composites.