| 摘要 |
PURPOSE: Provided is a manufacturing method of silica glass by extruding silica sol composed of colloidal sol, and silicon alkoxide hydrolyzed under basic catalyst. The resultant silica glass has high purity and high strength, enabling long and large-sized silica rods and tubes. CONSTITUTION: The method comprises the steps of: preparing a sol by mixing colloidal silica(fumed silica+deionized water) with dispersant, organic base such as tetramethylammonium hydroxide, to be pH11 or higher; hydrolyzing silicon alkoxide (Si(OR)4) having two alkoxide groups, as diethoxydiethylsilane or diethoxydiphenylsilane, under basic catalyst, NH4OH; mixing the sol with hydrolyzate, where a gelling agent, as methyl lactate or ethyl lactate, is added; filling an extruder with the sol; gelling by heating under 100deg.C; extruding; drying in a chamber; thermal-treating at low temperature, with HCl, He, H2 or O2 gas flowing for removing impurities in dried gel; sintering at 1400deg.C in He gas atmosphere.
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