Fabrication and Characterization of Carbon Fiber/Ceramic Composites Prepared through Sol-Gel Impregnation of TEOS and Boehmite

• Main Authors: Si-Ying Chen, 陳思穎
• Other Authors: Kuo-Jung Lee
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/78922169541778776045

碩士 === 義守大學 === 材料科學與工程學系碩士班 === 95 === The study is to investigate the mechanical, tribological and anti-oxidation properties of carbon fiber/ceramic composites prepared through sol-gel impregnation of TEOS, Boehmite and TEOS/Boehmite. The carbon fiber cloth surface was coated with a different layer of ceramic through different sol-gel impregnation and sintering temperature. Oxidation tests show that those sol-gel impregnated specimens exhibit better anti-oxidation behavior than that of pure carbon fiber. Among all sol-gel impregnated specimens, the TEOS sol-gel impregnated specimens display the worst anti-oxidation behavior. The Boehmite sol-gel impregnated specimens had the highest oxidation temperature at the beginning stage of oxidation. In addition, the TEOS/Boehmite impregnated sol-gel specimens had the highest oxidation temperature at the finishing stage of oxidation. Bending test results show that bending strength of various sol-gel impregnated specimens were higher than that of pure carbon fiber specimen. The Boehmite sol-gel impregnated specimens sintered at 1200℃ and 1300℃ had the highest bending strength. In addition, the Boehmite and TEOS/Boehmite sol-gel impregnated specimens sintered at 700℃ and all the TEOS sol-gel impregnated specimens had the lowest handing strength. Wear test results display that the Boehmite and TEOS/Boehmite sol-gel impregnated specimens sintered at 1200℃ and 1300℃ had higher and more stable friction coefficient, and lower weight loss than the specimens sintered at 700℃. It seems that those ceramic derivatives such as α-Al2O3, Mullite etc. from sol-gel at higher sintering temperature, could improve and stabilize the friction coefficient during wear tests. Furthermore, due to the large difference of thermal expansion coefficient between the amorphous SiO2 derived from TEOS sol-gel and carbon fiber. The adhesion between the SiO2 and carbon fiber, and it was easy to break loose during the wear test. This caused the friction coefficient to become unstable and the weight loss to increase.