摘要
利用溶胶-凝胶酸碱二步催化法和常压干燥法制备了低密度多孔xSiO2-（10-x）Al2O3干凝胶，其中x分别取9、8、7和6.SiO2凝胶按照摩尔比为正硅酸乙酯（TEOS）：水：无水乙醇：盐酸：氨水=1：4：7：7．5×10^-4：0．0375制备，作为二元复合氧化物的网络骨架；Al2O3由廉价的无机铝盐Al（NO3）3·9H2O与氨水反应制得．采用小角X射线散射（SAXS）实验，比较研究了不同铝含量SiO2-Al2O3干凝胶以及6SiO2-4Al2O3干凝胶不同热处理温度下的分形特性．结果表明。随着铝含量的增多。分形特性的范围逐渐增加，构成干凝胶的胶体颗粒尺度相应减小．胶体颗粒的尺度为14—16nm；对于铝质量分数为40％的干凝胶，满足分形特性的颗粒范围随着热处理温度的升高而增大．
Low-density xSiO2 - （10 - x were prepared by sol-gel and non-superc nary composite materials, formed from TE Al2O3 xeroge tical drying. OS by hydrol ls with x = 0. 9, 0. 8, 0. 7 and 0. 6 （ mole fractions） Silica alkogels, which were the network supports of biytic condensation with a molar ratio of TEOS： H2O： alcohol： HCl： ammonia = 1 ： 4：7： 7.5 × 10 ^-4： 0. 0375. Aluminumhydroxide derived from Al （ NO3 ） 3 and NH4 OH acting in the alcohol solution under the condition of catalysts. The fractal characteristic of SiO2-Al2O3 xerogels with different aluminum content and 6SiO2-4Al2O3 ones under different heat treatment temperature was investigated by means of small-angle X-ray scattering （SAXS）. The results show that mass fractal range of SiO2 - Al2O3 xerogels increases and colloid particle decreases with the increase of aluminum content and the size of colloid particles are between 14 nm and 16 nm. For the SiO2 - Al2O3 xerogels of 40% aluminum content, fractal particle range is increased with the increase of temperature.
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2007年第5期790-793,共4页
Journal of Harbin Institute of Technology
