Carbon fiber reinforced SiC coating without cracks prepared by slurry
SiC coatings have been widely used as antioxidant or buffer layer on the C/C composites but faced with great difficulty resulting form the micro-cracks caused by thermal expansion mismatch between the SiC coating and the C/C substrate. Aiming at this problem, in the present paper, the SiC coatings prepared by slurry are reinforced by carbon fiber on C/C composites. The effect of carbon fiber content on the state of through-cross cracks in coatings is studied. Microstructure, phase distribution and composition of coating are characterized by SEM and XRD. The thermal shock resistance is investigated with the temperature of the sample decreasing from 1573K to room temperature in 2 minutes in the airflow. Two SiC phases ,α-SiC and β-SiC ,are contained in the coatings , and the two SiC phases closely integrate with each other into a loose but high strength structure which is benefit to alleviate thermal stress: the carbon fibers added to the SiC coatings restrains effectively cracks propagation through the mechanism of carbon fiber extraction and cracks deflection. With the content of carbon fiber increasing, cracks in SiC coatings decrease distinctly. Eventually, with 10wt％ carbon fibers, the SiC coating is free of cracks. After thermal cycling between 1573K and room temperature for 60 times, SiC coatings holds no micro-cracks and cohesive to the carbon/carbon composite substrate.
C/C composites SiC coatings carbon fiber reinforced thermal shock resistance
Huang Yong-Le Bai Shu-Xin Zhang Hong Ye Yi-Cong
Department of Materials Science and Applied Chemistry, National University of Defense Technology, Changsha 410073, China
国际会议
北京
英文
707-711
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）