Study on ablation behavior of ZrB₂-SiC coating based on the high thermal conductivity substrate

The ZrB₂-SiC coatings were prepared on SiC-coated 3D C/C composites with different substrates by supersonic atmospheric plasma spraying. Ablation tests of 80 s and 20×4 s were carried out in an oxyacetylene flame with a heat flux of 2.38 MW/m² to evaluate the ablation resistance and thermal shock resistance of the ZrB₂-SiC coating. Results show that the substrate of the HTC-XZZ specimen provides long-distance heat transfer channels, leading to a reduction of 174 °C and 237 ℃ in the surface temperature of the coating, which weakens the SiO₂ consumption. Combined with the pinning stability of the sawtooth SiC inner layer on oxide film, ZrSiO₄ is formed, which improves the compactness of the coating and effectively prevents oxygen diffusion, has good structural stability, and exhibits excellent ablation resistance and thermal shock resistance. This new thermal structure coating shows great application prospects in the field of thermal protection of materials.