ZrC-SiC-C/C复合材料的制备及其烧蚀性能

Fabrication and ablation performances of ZrC-SiC-C/C composites

以低密度C/C为坯体,采用前驱体浸渍裂解法(PIP)制备ZrC-SiC-C/C复合材料,研究其微观结构和烧蚀性能,并探讨其抗氧化烧蚀行为。结果表明:ZrC-SiC双元陶瓷相弥散分布于基体中,且各相界面结合良好;ZrC-SiC-C/C复合材料表现出良好的抗氧化烧蚀性能,经2 200℃/120s等离子体烧蚀后,其线烧蚀率和质量烧蚀率分别为1.67×10^(-4) mm·s^(-1)和6.04×10^(-4) g·s^(-1)。烧蚀温度为2 200℃时,材料表面形成的ZrO_2-SiO_2二元共熔体系氧化膜,有效抑制氧化性气氛向材料内部的渗透,减缓火焰对材料的剥蚀作用;烧蚀温度为2 500℃时,材料表面形成以表层为ZrO_2和底层为ZrO_2-SiO_2二元共熔体系的氧化膜,其中ZrO_2层阻挡热量向内部传递,有助于底层形成致密的氧化层。

ZrC-SiC-C/C composites were fabricated by precursor infiltration and pyrolysis method （PIP） using the C/C with a low density as performs. The microstructure and ablation performance of the composites were investigated, and the anti-oxidant ablation behavior was discussed, particularly. The results show that ZrC-SiC dual ceramic phases are dispersed in the matrix, and a good interface between different phases is obtained; ZrC-SiC-C/C composites have an excellent anti-oxidant ablation performance. After ablation at 2 200℃ for 120 s by plasma flame, the linear and mass ablation rates of composites are 1.6710×10 ^-4 mm·s^-1 and 6.04×10 ^-4 g·s^-1, respectively. When the ablation temperature is 2 200℃, ZrO2-SiO2 binary eutectic systemas a oxide film is formed on the surface, which can effectively prevent the infiltration of oxidation atmosphere, and reduce the denudation of flame on the material. When the ablation temperature rises to 2 500℃, aoxide membrane structure with the ZrO2 as the outer layer and ZrO2 SiO2 binary eutectic system as the inner layer is generated on the surface. ZrO2 layer can inhibit heat transmitting into interior, which contributes to form a dense oxide layer at the bottom.