Effects of SiC interfacial coating on mechanical properties of carbon fiber needled felt reinforced sol-derived Al2O3 composites
(Science and Technology on Advanced Ceramic Fibers & Composites Laboratory, National University of Defense Technology, Changsha 410073, China)
Abstract: 3D carbon fiber needled felt and polycarbosilane-derived SiC coating were selected as reinforcement and interfacial coating, respectively, and the sol-impregnation-drying-heating (SIDH) route was used to fabricate C/Al2O3 composites. The effects of SiC interfacial coating on the mechanical properties, oxidation resistance and thermal shock resistance of C/Al2O3 composites were investigated. It is found that the fracture toughness of C/Al2O3 composites was remarkably superior to that of monolithic Al2O3 ceramics. The introduction of SiC interfacial coating obviously improved the strengths of C/Al2O3 composites although the fracture work diminished to some extent. Owing to the tight bonding between SiC coating and carbon fiber, the C/SiC/Al2O3 composites showed much better oxidation and thermal shock resistance over C/Al2O3 composites under static air.
Key words: alumina; carbon fiber reinforcement; interfacial coating; mechanical properties; oxidation resistance; thermal shock resistance