| 摘要 |
PURPOSE:To prevent cracking during preparation of gel and its sintering and to obtain an optically and mechanically homogeneous quartz glass by properly adjusting the pH of a raw material compsn. consisting of metal alkoxide ultrafine silica powder, etc. at the time of its feed. CONSTITUTION:The raw material compsn. consisting of metal alkoxide, ultrafine silica powder, water, acid, alcohol, etc. is exactly adjusted to 4-6pH at the time of its feed by adding aq. ammonia or the like alkali. This sol soln. is dried to form a gel and it is sintered to form quartz glass. This method strengthens the gel structure, and seldom causes cracking, though large contraction of the volume occurs at the time of formation of dry gel. Therefore, large dry gel can be formed. Since this dry gel seldom causes cracking during sintering, a large quartz glass plate can be formed. |
