加热方式对C／SiC复合材料结构与性能的影响

利用化学气相浸渗法制备了 C/ Si C复合材料 ,研究了两种加热方式 (电阻加热和中频感应加热 )下 Si C沉积物形貌、沉积机制以及复合材料结构和性能。结果表明 :电阻加热时沉积单元为高温熔滴 ,Si C沉积物为卵石形貌 ;感应加热时沉积单元为 Si C固体粒子 ,Si C沉积物为粒状形貌。电阻加热时高温熔滴易于渗入纤维束内部 ,复合材料结构均匀 ,致密度高 ;而感应加热时 Si C固体粒子多以团聚体的形式沉积在纤维束表面 ,难于渗入纤维束内部 ,复合材料结构均匀性差 ,难以致密。沉积机制的差异导致两种复合材料的结构差异 ,使得复合材料的力学性能不同 ,电阻加热时复合材料弯曲强度、断裂韧性和断裂功较高 ;感应加热时复合材料性能较低

Effect of heating method on the microstructure and properties of C/SiC composites

C/SiC composites were fabricated by lower pressure chemical vapor infiltration Effect of two kinds of heating method (electrical resistance heating at 50 Hz and induction heating at 2500Hz) on deposition mechanism of SiC, the densification, microstructure and properties of C/SiC composites was investigated The difference of deposition mechanisms of SiC between the different heating methods was indicated by deposition unit Deposition unit is high temperature molten droplet for electrical resistance heating However it is SiC solid agglomerate for induction heating It is difficult for SiC composites to densify for induction heating because it is difficult for SiC solid agglomerate to infiltrate into fiber bundle But it is easy for high temperature molten droplet to infiltrated into fiber bundle C/SiC composites infiltrated under two kinds of different heating method have different microstructure due to different SiC deposition mechanism This led to C/SiC composites to have higher density,bending strength,fracture toughness and work of fracture for electrical resistance heating as compared with induction heating