Long-life ablation resistance ZrB₂-SiC-TiSi₂ ceramic coating for SiC coated C/C composites under oxidizing environments up to 2200 K

To improve the ablation resistance of carbon/carbon (C/C) composites at temperature about 2200 K, a ZrB₂-SiC-TiSi₂ ultra-high temperature ceramic coating was prepared by supersonic atmosphere plasma spraying on SiC coated C/C composites. The ZrB₂-SiC-TiSi₂ coating could protect C/C composites for more than 240 s under heat flux of 2400 kW/m². The maximum surface temperature of the sample can reach to 2230 K. In addition, the mass and linear ablation rates of the coated samples after ablation for 240 s are only (0.314 ± 0.065) × 10⁻³ g/s and (0.221 ± 0.026) × 10⁻³ mm/s, respectively. The ZrB₂-SiC-TiSi₂ coating was converted into three layers after ablation: an outer layer, a particle-stacking layer, and a molten filled layer. The production of ZrTiO₄, acting as sintering additive, could promote the sintering of ZrO₂ and fill the pores, which effectively improved the ablation resistance of ZrB₂-SiC-TiSi₂ coating.