在多孔C/SiC中渗入SiB4微粉后,采用先驱体浸渍裂解(PIP)结合化学气相渗透(CVI)法进行致密化制备C/SiC—SiB4复合材料。利用XRD、EDS、SEM分析了材料的组分及微结构。研究了材料在500~1000℃静态空气的氧化行为,并与致密C/SiC复合材料的氧化行为进行了比较。结果表明,SiB4主要渗入到纤维柬间,它与随后PIP及CVI法引入的SiC较好地结合在一起。在氧化过程中,SiB。起自愈合作用,它能减缓碳纤维和界面的氧化。在600~900℃氧化10h后,C/SiC—SiB4的失重率均比致密C/SiC小,抗弯强度没有明显降低,且均比致密C/SiC高。
SiB4 powder was infiltrated into porous C/SiC, then a C/SiC-SiB4 composite was densified by using polymer infiltration and pyrolysis (PIP) combined with chemical vapor infiltration (CVI) process. Phase composition and microstructure of the composite were characterized by XRD, EDS and SEM. Oxidation behavior of the composite was investigated in air at temperatures ranging from 500 to 1000℃, and compared with that of densified C/SiC. The results showed that the powder was infiltrated mainly into inter-bundle pores of the as-fabricated composite. It was combined with the subsequent infiltrated SiC very well. The SiB4 powder can hinder the inwards diffusion of oxygen in air, and protect the carbon fibres and interphase from oxidation. At the temperature of 600-900℃ after oxidation for 10h, the weight loss rate of the C/SiC-SiB4 composites were less than that of densified C/SiC. The flexural strengths of both C/SiC-SiB4 composites did not decrease obviously, which was higher than that of densified C/SiC.