BaO-Al_2O_3-SiO_2系玻璃的溶胶-凝胶工艺研究

讨论了多元醇盐水解缩聚的溶胶 -凝胶工艺制备 BAS( Ba O- Al2 O3- Si O2 )玻璃时 ,加水方式和加水量 ,醇盐含量和醇盐酸碱性、溶剂含量以及陈化温度对凝胶形成、胶凝时间和凝胶玻璃结构的影响。实验成分范围 ( wt% )为 Si O2 ∶ 34～ 5 0 ,Al2 O3∶ 1 0～ 30 ,Ba O∶ 2 4～ 48,Li2 O∶ 0～ 5。结果表明 ,采用正硅酸乙酯预水解方式 ,水和醇盐摩尔比 >6～ 8,正硅酸乙酯 >40 mol%或异丙醇铝 <40 mol% ,可以获得具有 80 %以上架状、纯架状网络结构 ,断键程度 <1 2 %的均匀透明凝胶玻璃。增加加水量和提高陈化温度可以缩短胶凝时间

A STUDY ON THE SOL-GEL PROCESS FOR BAS (BaO-Al_2O_3-SiO_2) GLASSES

The influence of water addition sequence and water quantity, quantity and acidity and basicity of alkoxides, solvent quantity and temperatur eduring gelling process on the forma tion ofgel, gelation time and structure of gel glasses were studied for the sol-gel process fabricating BASglasses. The composition ranges of the glasses (wt%) are BaO: 24～48, Al2O3: 10～30, SiO2:34～50 and Li2O: 0～5。The results show that the homogeneous transparentgels can be gained bya partial hydr olysis of tetraethy silicate and optimum parameters of hydrolysis process, when themolration of water to alkoxides is more than 6～ 8, and when tetraethyl silicate is more than40mol% or aluminum is opropoxide is less than 40mol%. The gel glasses have over 80% framenet work structure and the degee of broken bond is below 12%. The gelation time decreases withthe increase of water quantity and with the rise in temperature during gelation.