Exceptional Long-Duration Ablation Tolerance over 2500 °C of C/ZrC–SiC–Cu3Si–Cu Interpenetrating Composites

• • After 1200 s of oxyacetylene ablation at 2557–2600 °C, the composite achieves mass and linear ablation rates of 0.0604 mg·cm−2·s−1 and 0.1808 μm·s−1, respectively, representing a near-zero ablation regime that exceeds conventional C/ZrC–SiC by more than an order of magnitude; this enables long-duration thermal protection for reusable hypersonic vehicles and rocket nozzles where current materials fail within seconds. • • The composite maintains a surface temperature of approximately 2300 °C under a heat flux of 3.18 MW·m−2 for 1200 s, significantly lower than the 2557–2600 °C of the C/ZrC–SiC reference, due to transpiration cooling from continuous evaporation of uniformly dispersed Cu-containing phases; this active cooling mechanism reduces thermal gradients and extends component lifetime under sustained extreme heat loads. • • Mechanical properties include 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, surpassing most reaction-melt-infiltration-derived C/ZrC–SiC; these values indicate that the interpenetrating metal-ceramic architecture provides damage tolerance without sacrificing ablation resistance, critical for load-bearing thermal structures. • • The composite exhibits a density of 3.0 g·cm−3 and an open porosity of 3%, achieved through Zr–Si–Cu melt infiltration into carbon fiber-reinforced carbon aerogel preforms; this low porosity and uniform matrix are essential for preventing oxygen ingress and mechanical denudation, offering a scalable fabrication route for complex-shaped components.