C／C-SiC复合材料的反应熔渗法制备与微观组织  

Preparation and Microstructure of C/C-SiC Composites by Reactive Melt Infiltration

作　　者：赵彦伟[1] 孙文婷[1] 李军平[1] 刘宏瑞[1] 张国兵[1] 

机构地区：[1]航天材料及工艺研究所,先进功能复合材料技术重点实验室,北京100076

出　　处：《宇航材料工艺》2013年第2期64-69,共6页Aerospace Materials & Technology

摘　　要：采用无压反应熔渗法在1 550℃下将熔融Si或Si0.9Zr0.1浸渗入多孔C/C预制体中制备了高致密的C/C-SiC复合材料。系统研究了多孔C/C预制体中酚醛树脂热解碳(PIP-C)和化学气相渗透碳(CVI-C)对反应熔渗Si或Si0.9Zr0.1的浸渗行为、反应程度、物相成分和微观组织的影响。结果表明:熔融Si或Si0.9Zr0.1完全渗入到相邻碳纤维束间的大孔和碳纤维形成的小孔中,多孔PIP-C/C预制体较易浸渗,且反应较充分,熔渗Si0.9Zr0.1后复合材料中除了生成大量SiC外,还有少量ZrC和ZrSi2生成,未发现游离Si。多孔PIP-C/C预制体中部分碳纤维与熔体反应,损伤纤维,而多孔CVI-C/C预制体中的沉积碳仅与熔体反应生成了一薄层,很好地保护了碳纤维,保持了碳纤维的高性能。提出反应熔渗制备C/C-SiC复合材料的形成机制:由初期的溶解-沉淀控制和后期的C向SiC层扩散控制为主。A high relative desity C/C-SiC composites were prepared by pressureless reactive infiltration of mol- ten Si or Si0.9Zr0.1 alloy into the porous C/C preform at 1 550℃. Effects of different carbon matrixes of porous C/C preform including pyrolytic carbon and chemical vapor deposited carbon on the behaviors of melt Si or Si0.9Zr0.1 alloy infiltration into the porous perform, the degree of reaction, the reaction phases contents and microstructures were in- vestigated. The results showed that the molten Si or Si0.9Zr0,l alloy was infiltrated into the large pores among adjacent carbon fiber bundles and some small pores among carbon fibers. The melts were infiltrated more easily into the porous C/C preform with pyrolytic carbon and reacted completely between pyrolytic carbon and melts. The composite was composed of SiC, ZrC, ZrSi2 phases and without free Si. Some carbon fibers reacted partially with melt in the porous C/C preform with pyrolytic carbon, which leaded to potential damage of the carbon fibers. However, the chemical va- por deposited carbon of outer surface of the carbon fiber only reacts with infiltrating melts to form a thin SiC layer, which protected carbon fibers and maintained the improved performances. The microstructural formation mechanism of the C/C-SiC composites prepared by reactive melt infiltration was proposed：the formation of the early stage was con- trolled by solution-precipitation, and the subsequent growth was controlled by diffusion of C through the SiC layer.

关 键 词：多孔C C预制体 C C—SiC复合材料 反应熔渗法 微观组织 化学气相渗透 

分 类 号：TB332[一般工业技术—材料科学与工程]