| abstract |
(57) Abstract: In a fused silica product prepared from silica particles or a porous silica body, internal defects such as seed crystals and voids are eliminated. SOLUTION: A raw body made of silica glass particles is placed in a chamber and the raw body is dried by raising the temperature of the chamber to 1720 ° C while purging the chamber with helium or evacuating the chamber. And sinter. At least the temperature in the chamber Sintering by raising the temperature to 1750 ° C, introducing an inert gas into the chamber at a pressure of less than about 6.9 MPa, and cooling the chamber while maintaining the pressurized atmosphere at a temperature at least lower than the annealing point of silica glass. Solidify the body. |