ZrC改性C/C-SiC复合材料的力学和抗烧蚀性能

采用碳纤维针刺预制体, 用前驱体浸渍裂解(PIP)法分别制备了C/C-SiC和C/C-SiC-ZrC陶瓷基复合材料, 并对材料的微观结构、力学和烧蚀性能进行了分析对比。结果表明:利用该方法可制备出陶瓷相填充充分且分布均匀的复合材料。C/C-SiC-ZrC的面内弯曲强度、厚度方向的压缩强度、层间剪切强度均低于对应的C/C-SiC的。2 200 ℃、600 s氧化烧蚀后, C/C-SiC-ZrC的抗烧蚀性能显著优于C/C-SiC, 其线烧蚀率下降43.8%, 质量烧蚀率下降25%。在超高温阶段, C/C-SiC-ZrC复合材料基体的ZrC氧化生成的ZrO₂溶于SiC氧化生成的SiO₂中, 形成黏稠的二元玻璃态混合物, 有效阻止了氧化性气氛进入基体内部。 

Mechanical and anti-ablative preformances of C/C-SiC composites modified by ZrC

Carbon fiber needling preform was used to prepare C/C-SiC and C/C-SiC-ZrC ceramics matrix composites by precursor infiltration and pyrolysis (PIP) process respectively. The microstructure, mechanical and ablation properties of materials were analyzed and compared. The results show that the composites produced by the method have sufficient filling and homogeneity distribution of ceramic phase. The in-plane flexural strength, compression strength through thickness direction and interlaminar shear strength of C/C-SiC-ZrC are all lower than the corresponding properties of C/C-SiC. C/C-SiC-ZrC shows better anti-ablative preformances compared with C/C-SiC after ablation at 2 200 ℃ for 600 s, the linear ablation rate is reduced by 43.8% and the mass ablation rate is reduced by 25%. During ultra-high temperature stage, the ZrC and SiC in the matrix of C/C-SiC composites are oxidized into ZrO₂ and SiO₂, which form a kind of viscous binary glassy mixture. The mixture could effectively prevent oxidizing atmosphere into the matrix.