Difference of Mullite Whiskers between Ytterbia-Doped Aluminum Hydroxide-Silica Gel and Mechanochemical Process  

作　　者：梁龙 李建保 林红 郭钢锋 何明生 

机构地区：[1]State Key Laboratory of New Ceramics and Fine Processing,Department of Materials Science and Engineering,Tsinghua University

出　　处：《Journal of Rare Earths》2006年第z2期51-53,共3页稀土学报（英文版）

基　　金：Project supported by the National High Technology Research and Development Program of China (2004AA332060)

摘　　要：A number of processing routes were developed for the synthesis of mullite whiskers. Mullite whiskers that were derived from ytterbia-doped aluminum hydroxide-silica gel were studied; another process for preparing mullite whiskers from Al2O3-SiO2 oxide mixtures by mechanochemical method was encountered by chance. The method of ytterbia-doped aluminum hydroxide-silica was used to enhance mullite formation from gel. For adding ytterbia, mullite formation can take place at 1000℃and almost single-phase mullite can be achieved at 1150℃, which is a significantly lower temperature than mechanochemical method. This enhancement of mullite formation is also attributed to refinement of aluminum hydroxide-silica by gel. Furthermore, well-developed single-crystal mullite whiskers were produced from the gel powder instead of normal-shaped grains. The presence of YbO might have promoted the formation of nanosized Al2O3 particles, which then acted as a template leading to mullite whiskers at higher sintering temperature.A number of processing routes were developed for the synthesis of mullite whiskers. Mullite whiskers that were derived from ytterbia-doped aluminum hydroxide-silica gel were studied; another process for preparing mullite whiskers from Al2O3-SiO2 oxide mixtures by mechanochemical method was encountered by chance. The method of ytterbia-doped aluminum hydroxide-silica was used to enhance mullite formation from gel. For adding ytterbia, mullite formation can take place at 1000℃and almost single-phase mullite can be achieved at 1150℃, which is a significantly lower temperature than mechanochemical method. This enhancement of mullite formation is also attributed to refinement of aluminum hydroxide-silica by gel. Furthermore, well-developed single-crystal mullite whiskers were produced from the gel powder instead of normal-shaped grains. The presence of YbO might have promoted the formation of nanosized Al2O3 particles, which then acted as a template leading to mullite whiskers at higher sintering temperature.

关 键 词：mullite whiskers ytterbia-doped GEL MECHANOCHEMICAL rare earths 

分 类 号：O614.322[理学—无机化学]