Exceptional Long-Duration Ablation Tolerance over 2500 °C of C/ZrC–SiC–Cu3Si–Cu Interpenetrating Composites
Carbon fiber-reinforced ultrahigh-temperature ceramic composites (C/UHTCs) based on ZrC–SiC are limited by rapid ablation above 2500 °C under prolonged oxidizing exposure. This study reports C/ZrC–SiC–Cu3Si–Cu interpenetrating composites fabricated by infiltrating a Zr–Si–Cu ternary melt into carbon fiber-reinforced carbon aerogel (C/CA) preforms. The process yields a uniform metal-ceramic matrix via ceramization of the carbon aerogel and in situ precipitation of Cu-containing phases. During oxyacetylene ablation at a surface temperature of 2557–2600 °C for 1200 s, the composite exhibits mass and linear ablation rates of 0.0604 mg·cm−2·s−1 and 0.1808 μm·s−1, respectively, surpassing conventional C/ZrC–SiC and other reported ceramic and ceramic-metal matrix composites under similar conditions. The ablation resistance arises from transpiration cooling via continuous evaporation of dispersed Cu-containing phases, which maintains a surface temperature of approximately 2300 °C under a heat flux of 3.18 MW·m−2, combined with a protective Zr–Si–O glassy layer that inhibits oxygen diffusion and resists mechanical denudation. The composite also demonstrates a flexural strength of 194±7 MPa, a fracture toughness of 11.8±1.2 MPa·m1/2, and a work of fracture of 5315±1232 J·m−2, exceeding most reaction-melt-infiltration-derived C/ZrC–SiC. These properties are attributed to the highly reactive carbon aerogel matrix, a protective PyC interface, optimized interfacial debonding, crack deflection mechanisms, and compressive residual stresses. The combination of active-passive cooling and robust mechanical performance positions this composite as a candidate for structural applications in extreme thermal-mechanical environments.