| 摘要 |
PURPOSE:To readily obtain large-sized silica glass without causing crack or fracture at a low cost, by gelatinizing a silica sol prepared by hydrolyzing a silicon alkoxide and/or polycondensate thereof to give a silica sol, gelatinizing the silica sol, drying the resultant gel in an alcoholic vapor atmosphere and sintering the resulting gel. CONSTITUTION:Water in which pH is preadjusted, as necessary, with an acid or alkali is added to a silicon alkoxide expressed by formula I (R is alkyl) and/or polycondensate thereof expressed by formula II (n is 0-8), etc., and, as necessary, an alcohol is added to give a homogeneous solution, which is hydrolyzed to afford a silica sol. The formed silica sol is then transferred to a suitable hermetically sealed vessel and gelatinized at >=0 deg.C. The gelatinized sol with the vessel is then transferred into an alcoholic vapor atmosphere to open the vessel. The resultant gel is then dried by controlling the alcohol vapor pressure at a temperature above room temperature and then sintered. |
