SiC-HfSi₂-TaSi₂ high temperature anti-ablation compound coating on carbon/carbon composites

To prevent the ablation of carbon fiber reinforced carbon (C/C) composites from high temperature, a silicon carbide-hafnium silicide-tantalum disilicide (SiC-HfSi₂-TaSi₂) compound coating with high temperature anti-ablation ability was prepared on the surface of C/C composites by a calcining technique of pack cementation. The anti-ablation behavior of C/C composites was evaluated by an oxyacetylene flame. The morphologies, element distribution and phase composition of the surface and cross-sections of the SiC-HfSi₂-TaSi₂ coating before and after ablation were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The results show that, because of the good stability of the HfO₂ and Ta₂O₅ formed during ablation, the SiC-HfSi₂-TaSi₂ coating exhibits favorable anti-ablative properties. The linear ablation rate of C/C composites with the SiC-HfSi₂-TaSi₂ coating is 0.009 mm/s, and the mass ablation rate is 0.00385 g/s at 3000°C after ablation for 20 s.