The development of materials capable of withstanding long-term ablation above 2500  °C in an oxidizing atmosphere remains a critical challenge. Although conventional C/ZrC–SiC composites show promise for ultrahigh-temperature applications, they typically suffer from high ablation rates under prolonged exposure. To address this limitation, we fabricated novel C/ZrC–SiC–Cu₃Si–Cu composites by infiltrating a Zr–Si–Cu ternary melt into carbon fiber-reinforced carbon aerogel (C/CA) preforms. This process resulted in the formation of a uniform, interpenetrating metal-ceramic matrix through the ceramization of CA accompanied by precipitation of Cu-containing phases from the melt. Relying on sweat gland-like channel migration heat dissipation and evaporative heat removal of metallic phases as well as mechanical denudation resistance and inhibition of oxygen diffusion by the Zr–Si–O layer, the composite exhibited exceptional long-term ablation resistance. After 1200 s of oxyacetylene ablation at a surface temperature of 2557–2600 °C, the composite exhibited ultralow mass and linear ablation rates of 0.0604 mg·cm⁻²·s⁻¹ and 0.1808 μm·s⁻¹, respectively, surpassing the benchmark performance of conventional C/ZrC–SiC as well as other reported ceramic matrix and ceramic-metal matrix composites under similar test conditions. Moreover, the composite demonstrated excellent mechanical properties, with a flexural strength of 194±7 MPa, a fracture toughness of 11.8±1.2 MPa·m^1/2, and a work of fracture of 5315±1232 J·m⁻², exceeding those of most reaction-melt-infiltration-derived C/ZrC–SiC. This favorable combination of ablation resistance and mechanical performance makes the composite a promising candidate for structural applications in extreme thermal-mechanical environments.

Preparing antioxidant coatings to address the inherent oxidation sensitivity of carbon fiber-reinforced carbon aerogel (C/CA) composites is a feasible way to promote their application in oxidizing environments as thermal insulation materials. However, preparing the coatings with excellent oxidation and ablation resistance while avoiding evident damage to the C/CA substrate still remains a challenge. Herein, a SiC@SiO₂ nanowire-toughened ZrB₂–SiC/SiC bilayer coating with a large thickness of 500 μm was prepared on C/CA using a one-step low-temperature reaction sintering method, which simultaneously formed a sintered outer layer with even-distributed nanowires and a siliconized gradient inner layer. By courtesy of the synergic thermal response of the layers and the crack deflection induced by the nanowires, the resulting coating has moderate residual compressive stress of 0.08–1.22 GPa in the interface, high interfacial bonding strength of 6.02 MPa, and good fracture toughness of 4.36 MPa·m^1/2. Benefited from the optimum components and improved structure, the coating shows excellent cyclic ablation resistance with linear ablation rates of 0.1 μm/s at 1650 ℃ for 1500 s (300 s × 5 cycles) and 0.4 μm/s at 1850 ℃ for 900 s (300 s × 3 cycles). The one-step preparation strategy contributes to little damage to the substrate, thus showing the well-preserved mechanical and thermal insulation properties.