SiO2凝胶/铝硅纤维复合材料的高温损坏机理研究  

Fabrication of SiO_2 Gel/Alumina-silica Fiber Composite and Its Damage Mechanism at High Temperature

作　　者：张晶[1] 田庚[1] 王明超[1] 刘家臣[1] 

机构地区：[1]天津大学材料科学与工程学院,先进陶瓷加工技术教育部重点实验室,天津300072

出　　处：《硅酸盐通报》2015年第10期2934-2939,共6页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51272171,51372164)

摘　　要：本文采用浸渍法制备了SiO2凝胶/铝硅纤维复合材料,通过分析材料的热失重-差示扫描热、微观形貌、物相组成及热传导等特性,得出了复合材料高温损坏机理。研究结果表明,SiO2凝胶/铝硅纤维复合材料相对于硅铝纤维,析晶温度可提高200℃;随着热处理温度由900℃升至1200℃,复合材料的气孔率由55%升至75%,体积密度由0.85 g/cm3降至0.45g/cm3,导热系数由0.0767W/(m·K)增至0.0908W/(m·K),压缩回弹率由90%降至43%;当热处理温度达到1200℃,复合材料的力学性能损坏,主要原因是莫来石和方石英的析晶,以及硅凝胶与纤维之间的粘结失效。The SiO2 gel/alumina-silica fibre composite which could be widely used in the thermal sealing field was fabricated by impregnation in this study.The theral gravimteric-differential scanning calorimeter（ TG-DSC） microstructure,phases composition,apparent porosity and thermal conductivity of composites were investigated after the heat-treatment at different temperatures for 1h.The results showed that the crystallization temperature of SiO2 gel/alumina-silica fiber composite,comparing with alumina-silica fiber,increased by 200 ℃.In the range of the temperature 900-1200 ℃,the porosity increased from55% to 75%,the density decreased from 0.85 to 0.45g/cm^3,the thermal conductivities raised from 0.0767 to 0.0908W/（ m · K） and the compression resilience ratios declined from 90% to 43%.The mechanical properties of the composites were destroyed after the heat-treatment at 1200 ℃,for the reasons that the crystallization of mullite and cristobalite and the adhesive failure between gel and fibers.

关 键 词：SiO2凝胶/铝硅纤维复合材料 压缩回弹 导热系数 

分 类 号：TB35[一般工业技术—材料科学与工程]