| 摘要 |
PURPOSE:To obtain quartz glass having high quality effectively and economically by hydrolyzing alkyl silicate with acidic reagent, and adding a salt contg. no metal ion to sol obtd. by mixing superfine particles of silica with the hydrolyzate. CONSTITUTION:Sol is prepd. by mixing a soln. obtd. by the hydrolysis of alkyl silicate using an acidic reagent, with superfine silica powder in a specified proportion. A salt contg. no metal ion is added to the sol. Suitable salt is ammonium salt such as NH4Cl. (NH4)2SO4, etc., and suitable amt. to be added is pref. 0.1-30wt% basing on the weight of the quartz glass after sintering. Then, the sol contg. the salt is dried to dry gel, which is treated in He atmosphere or in vacuum to close the pores in the dry gel. The procedure for closing the pores is executed at a lower temp. by the addn. of the above-described salt, reducing thus loads on the furnace or jigs in the furnace. The glass or precursor of the glass obtd. by this method is held by heating at 1,500-2,200 deg.C to decompose the above described salt. Thus, quartz glass having high quality is obtd. |
