Effect of fiber type on the ablation resistance of sharp leading-edge C/C-ZrB₂-SiC composites: mesophase pitch carbon fibers vs. PAN-based fibers

To enhance the ablation resistance of sharp leading-edge carbon/carbon (C/C) composites, ZrB₂-SiC was introduced into them by a combined technique of vacuum filtration and chemical vapor deposition (CVD). The effect of fiber type, hybrid high thermal conductivity mesophase pitch carbon fiber (CF_MP) and PAN-based fibers (CF_PAN), on the ablation resistance of the C/C-ZrB₂-SiC composites was systematically evaluated under an oxyacetylene flame exposure at a heat flux of 2.38 MW/m² for 60s. Compared with the C/C-ZrB₂-SiC composite reinforced only by CF_PAN, the surface temperature of hybrid CF_MP/CF_PAN-reinforced C/C-ZrB₂-SiC composite decreased by ∼386 °C (a 17 % reduction) along with 15 % and 53 % lower mass and linear ablation rates, respectively. The superior ablation resistance is attributed to the efficient heat dissipation, thereby mitigating stagnation point ablation of the sharp leading edge. These findings present a viable strategy for engineering next-generation thermal protection components with excellent oxidation/ablation resistant performance.