Ablation behavior and mechanism of double-layer ZrB₂-based ceramic coating for lightweight carbon-bonded carbon fiber composites under oxyacetylene flame at elevate temperature

Ablation behavior of double-layer ZrB₂-based ceramic coating for lightweight ZrB₂modified carbon-bonded carbon fiber (CBCFs/ZrB₂) composites was tested under an oxyacetylene flame at elevate temperature (1500, 1600 and 1700 °C) for 600s. The results indicate that the ablation temperature has significant effect on the microstructure and ablation behavior of the coated CBCFs/ZrB₂composites. The as-prepared coating could efficiently protect CBCFs/ZrB₂composites against oxidation from 1500 to 1700 °C for 600s. The ZrB₂-based ceramic coating had a good self-healing ability at 1500 °C and 1600 °C. With the increasing ablation temperature to 1700 °C, the coating exhibited severe ablation. However, the molten SiO₂from the coating seeped into the CBCFs/ZrB₂composites forming a coating layer on the carbon fibers surface which acted as an efficacious oxidation protective barrier.