Anti-ablative property of (C/C)/SiC-ZrC composites with different ZrC content

The (C/C)/SiC-ZrC composites with different ZrC content were fabricated by precursor infiltration and pyrolysis (PIP) process, and effects of the ZrC content on the microstructures and anti-ablative properties of the (C/C)/SiC-ZrC composites were investigated. The results show that after oxyacetylene ablation 600 s, the surface of (C/C)/SiC composites are loose, and a rather large ablation pit appeared. Whereas the surface of (C/C)/SiC-ZrC composites are compact relatively and coverd by white oxide. Compared with (C/C)/SiC composites, ablation rate of (C/C)/SiC-ZrC composites with different ZrC content decreases. When the ZrC content is low, ZrO₂-SiO₂ binary eutectic systems a oxide film is formed on the surface, which can effectively prevent the infiltration of oxidation atmosphere, and also the oxide melt and volatilize continuously, which can reduce temperature of ablation surface of the (C/C)/SiC-ZrC composites. When the ZrC volume fraction rises to 12.4vol%, outer ZrO₂ and inner SiO₂ are formed by the oxidation of ZrC and SiC, respectively. ZrO₂ is a excellent heat barrier material with low heat conduction coefficient, which can alleviate the heat diffusion of ablation area during ablation, leading the higher surface temperature of the (C/C)/SiC-ZrC composites, but two dense oxidation film can prevent the corrosion of oxidation atmosphere, resulting in a good ablation resistance of (C/C)/SiC-ZrC composites.