ZrC改性C/C-SiC复合材料的烧蚀性能研究

Investigation on ablation performance of ZrC modified C/C-SiC composites

采用"化学气相渗透+先驱体浸渍裂解"(CVI+PIP)混合工艺,制备了ZrC改性C/C-SiC复合材料,研究了引入ZrC对改善C/C-SiC材料烧蚀性能的影响。结果表明,氧乙炔烧蚀600s后,C/C-SiC材料表面疏松,出现了大量孔洞;而同结构C/C-ZrC-SiC材料表面相对比较致密,被白色氧化物质覆盖,相比C/C-SiC材料,烧蚀率降低了一个数量级。C/C-ZrC-SiC材料氧化后形成了ZrO2-SiO2玻璃态熔融层,由于粘度较高,提高了与基体的粘附力,抵抗了氧乙炔气流的冲刷;而且熔融层能够有效降低氧化性气氛向材料内部扩散的速率,对于抑制材料的进一步氧化烧蚀起到了积极作用。

ZrC modified C/C-SiC composites were fabricated by ＂chemical vapor infiltration @ precursor impregation and pyrolysis＇combined process. Effects on improving ablation performances of C/C-SiC composites by introducing ZrC were investigated. The results showed that after oxyacetylene ablation 600s,the surface of C/C SiC composites were loose, and a great deal of holes appeared. Whereas the surface of C/C-ZrC-SiC composites had the same structure as C/C-SiC composites were compact relatively and covered by white oxide. Compared with C/C-SiC composites,ablation rate of C/C ZrC- SiC composites decreased one order of magnitude. C/C-ZrC-SiC composites formed ZrO2-SiO2 glassy molten layers after ox idation. Because of higher viscosity,ZrO2-SiO2 can enhance adhesive force and resist erosion of oxyacetylene airstream. Mo- reover, molten layers can reduce diffusion velocity of oxidizing atmosphere effectively, and had an active effect on restraining further oxidation ablation of C/C-ZrC-SiC composites.