Interface-engineered ceramization protects carbon at extreme temperatures

Carbon materials - whether in the form of fibers, yarns, or textiles - exhibit exceptional mechanical strength, low density, and high thermal and electrical conductivity, yet their rapid oxidation above ∼500 °C severely limits their performance in high-temperature environments. Conventional ceramic coatings provide only partial protection due to non-uniform coverage, thermal expansion mismatch, and microstructural defects. Here we present an interface-engineered dual-layer ceramization (IEDC) strategy that couples in-situ preceramic conversion with HfC layer to achieve conformal, adherent, and durable oxidation resistance. During pyrolysis, a dense nanocrystalline Hf-Si-C-N shell evolves from the preceramic precursor at the carbon interface, forming robust chemical bonds that block oxygen ingress and mitigate high-temperature erosion. This nanocrystalline interlayer acts synergistically with the outer HfC barrier, preserving structural integrity under extreme thermal flux. Thermogravimetric and high-temperature torch tests demonstrate that IEDC-treated carbon fibers (IEDC-CFs) retain nearly full mass in air and show only ∼1% mass loss after 60 s of exposure to a 1700 °C hydrogen torch, indicating outstanding oxidative and thermal stability. Infrared thermography and simulations further reveal a pronounced thermal-barrier effect, with a surface-to-backside temperature differential exceeding 300 °C under localized heating. Large-scale demonstrations on 3D-printed aircraft models confirm complete structural preservation at high temperature, while uncoated counterparts undergo catastrophic oxidation. By integrating interfacial ceramization with a robust external barrier, IEDC overcomes the adhesion and defect-sensitivity limitations of conventional coatings and enables uniform protection across complex carbon architectures. These features make IEDC a promising, scalable pathway for engineering oxidation-resistant carbon composites for aero-engines, thermal protection systems, and other extreme-environment components requiring long-duration thermo-oxidative durability. • Interface-engineered dual-layer ceramization protects carbon fibers. • Conformal Hf-Si-C-N interlayer with outer HfC barrier enables uniform coverage. • The preceramic derived ceramic-carbon composites retain nearly full mass in air and resist 1700 °C torch oxidation. • Scalable strategy for oxidation-resistant carbon composites in extreme environments.