合金反应熔渗法制备C/C-SiC-HfC复合材料(英文)

C/C-SiC-HfC Composite Prepared by Alloyed Reactive Melt Infiltration

采用22Hf78Si合金反应熔渗法制备了高性能低成本的C/C-SiC-HfC复合材料。首先采用化学气相渗透法增密碳纤维预制体得到多孔C/C复合材料预制体,然后在1700℃下反应熔渗22Hf78Si合金制备得到C/C-SiC-HfC复合材料。XRD分析表明复合材料由碳、SiC和HfC相组成。C/C-SiC-HfC复合材料的抗弯强度为237MPa,断裂模式为假塑性断裂模式。采用激光测试了反应熔渗C/C-SiC-HfC复合材料的抗烧蚀性能,复合材料的线烧蚀率为0.038mm/s,大大低于C/SiC复合材料的线烧蚀率0.081mm/s。烧蚀后复合材料烧蚀表面形成了一层HfO2烧蚀层,有效提高了复合材料的抗烧蚀性能。

A high performance and low cost HfC modified C/C-SiC composite （C/C-SiC-HfC） was prepared by 22Hf78Si alloyed melt infiltration. Carbon fiber felt was firstly densified by pyrolytic carbon using chemical vapor infiltration to obtain a porous C/C preform. 22Hf78Si alloyed melt was then infiltrated into the porous preform at 1700℃ to prepare the C/C-SiC-HfC composite. XRD analysis indicates that the resulting composite is composed of carbon, SiC and HfC. The as-received C/C-SiC-HfC composite, with the flexural strength of 237MPa, displays a pseudo-ductile fracture behavior. Ablation resistance of C/C-SiC-HfC composite was tested by a pulse laser. The linear ablation rate is 0. 038ram/s, which is much lower than that of C/SiC composite, 0. 081mm/s. A HfO2 barrier layer is formed on the ablation surface, which effectively protects the composite from severe ablation.