超快速溶胶-凝胶法制备高纯二氧化硅单块

Preparation of Monolithic Silica Glass by an Ultra fast Sol gel Process

传统的溶胶－凝胶工艺存在几个严重的缺点，例如，凝胶时间过长（２０ｄ以上），体积收缩太大（＞７５％），形状和尺寸无法控制以及严重的龟裂等［１］．这些缺点限制了它在技术上的应用．目前尚没有一种能在常温下短时间内制成具有良好光学性质的高纯度二氧化硅单块的方...

An ultra fast sol gel process has been developed to get high content silica materials, in which, the solvent tetrahydrofuran(THF) for hydrolysis of precursor tetraethyl orthosilicate, was removed through solvent extraction to obtain bulk sol. The bulk sol can be molded in different shapes such as discoid, pellet, octagon, cylinder, and half sphere. They solidified and gelled in a very short time in the presence of lithium salt. Measurements show that the silica monoliths possess volume shrinkage of 52%, high silica content of 82.4% and transmittance of 70% in the UV/Vis region, and are crack free indefinitely.