PURPOSE: To obtain a void-free gel, and produce a high-quality quartz glass, in the production of quartz glass by a sol-gel process, by dispersing silica fine powder under bubbling of nitrogen gas, etc., and using the obtained sol as a raw material.
CONSTITUTION: (1) A hydrolyzed solution is produced by mixing ethyl silicate with water, hydrochloric acid, and an alcohol, etc. (2) Fine silica powder is added to the solution and (3) dispersed under ultrasonic irradiation. (4) The coarse particles are removed by the centrifugal separation, (5) the pH of the dispersion is adjusted to 3.5W5.5 with an aqueous solution of NH3, and (6) the obtained sol is transferred to a specific vessel, gelatinized, dried and sintered. In the above process, the steps (2), (3) and (5) are carried out under N2 gas bubbling.
KANBE SADAO
TOKI MOTOYUKI
MIYASHITA SATORU
NAGAFUNE HARUO
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