摘要
以正硅酸乙脂、钛酸丁脂及Li、Al等的无机盐为原料,采用溶胶-凝胶工艺制备了Li_2O-Al_2O_3-SiO_2(LAS)玻璃陶瓷超细粉末。所得粉末的平均粒径为130 nm,比表面积为160 m^2/g。由差热分析、X射线衍射研究了LAS超细粉的核化与晶化过程。结果表明,超细粉的核化为表面核化,其核化温度与晶体析出温度,比类似组成的块状玻璃降低了100℃与100～200℃。由该超细粉制备的LAS陶瓷具有低的热膨胀系数α<10×10^(-7)℃^(-1)。
Ultrafine powders of Li_2O-Al_2O_3-SiO_2 (LAS) glass-ceramic were prepared by the sol-gel process using tetraethoxysilane, titanium butoxide, Li, Mg, Al(and Zn) inorganic salts as starting materials. The average particle size and specific surface area of prepared powders are 130nm, and. 160m^2/g respectively. The nucleation and the crystallization processes of LAS powders were also studied by DTA and X-ray diffractometer. The result shows that it is surface nucleation process for ultrafine LAS powders. Compared. with bulk LAS glassceramic having similar composition, the nucleation temperature and the crystallized temperature decreased by 100℃ and 100～200℃ respectively. The LAS glass-ceramics prepared by the ultrafine LAS powders have low thermal expansion coefficient, α<10 × 10^(-7)℃.
关键词
玻璃
陶瓷
核化
溶胶-凝胶法
晶化
sol-gel process
glass-ceramic
ultrafine powder
nucleation
crystallization
Li_2O-Al_2O_3-SiO_2 system
