反应熔渗法制备 C/C-ZrC 复合材料的微观结构及烧蚀性能

摘要

C/C-ZrC composites were fabricated by reactive melt infiltration (RMI).The densification behaviors of melt Zr infiltrating into different preforms were studied, subsequently, the resulting phases and characteristics were observed. Furthermore, the as-prepared C/C-ZrC composites from the preform with the optimal infiltration effect were selected for ablation test, and the ablation behaviors of C/C-ZrC composites under different temperatures were also investigated. The results show that the density of C/C-ZrC composite decreases with increasing the preform density. The porous C/C composite with density of 1.40 g/cm3 owns the best infiltration effect with the porosity decrease from 28.2% to 6.6%. Molten Zr reacting with the fibers and substrate carbon of the fiber web layers forms ZrC ceramic phase at the site of fiber web layers. The C/C-ZrC composites obtained by infiltrating Zr into preform with initial density of 1.40 g/cm3 is selected for ablation test, after ablation for 60 s, the linear ablation rate and mass ablation rate at 3 000 ℃ are −0.0033 mm/s and 0.004 2 g/s, respectively, and those at 2500 ℃ are 0.0080 mm/s and 0.0090 g/s, respectively. Thus, the anti-ablation properties of C/C-ZrC at 3000 ℃ prove to be superior to those at 2 500 ℃.%　　采用反应熔渗法(reactive melt infiltration， RMI)制备 ZrC 改性多孔 C/C 复合材料，研究不同孔隙度的C/C 多孔体在熔渗过程中的增密行为和渗 Zr 后的相组成及微观形貌，探寻具有最佳熔渗效果的 C/C 多孔体，并研究所得 C/C-ZrC 复合材料在不同温度下的氧乙炔焰烧蚀行为。结果表明，随 C/C 多孔体密度增加，C/C-ZrC 复合材料的密度降低；其中密度为1.40 g/cm3的多孔体熔渗效果最佳，开孔隙率由熔渗前的28.2%降低到6.6%。；熔渗的 Zr 液易与网胎层处的炭纤维和基体炭反应，生成的 ZrC 陶瓷相主要分布在原网胎层位置。择取原始密度为1.40 g/cm3的 C/C 多孔体熔渗后进行60 s 的氧乙炔焰烧蚀实验，在3000℃下的线烧蚀率和质量烧蚀率分别为−0.0033 mm/s 和0.0042 g/s，在2500℃下的线烧蚀率和质量烧蚀率分别为0.0080 mm/s 和0.0090 g/s，C/C-ZrC复合材料在3000℃下的抗烧蚀性能明显优于2500℃下的抗烧蚀性能。