Effect of Excess Free Carbon on Microstructure and Strength of SiC Fiber
游离碳对化学气相沉积SiC纤维微结构的影响

Analytical electron microscopy (AEM) was applied to investigate the effects of addition of free carbon on the microstructure of SiC fiber during chemical vapor deposition and the relation between microstructure of SiC fiber.The results indicate that carbon addition can effectively avoid WO3 formation at the W/SiC interface,and no oxygen element existed in fiber,while the grain size of SiC can be reduced,especially adjacent to W core.In addition,many concentric C rich layers formed within SiC.Above changes in microstructure can improve fiber's strength from 2800 MPa to 3600 MPa.