| 摘要 |
PURPOSE:To attain a reduced material loss in molding and obtain improved striae and compositional ununiformity by heating and press-molding natural or synthetic quartz glass in a graphite container in a vacuum followed by rapid cooling to a specified temp. CONSTITUTION:Natural or synthetic quartz glass is heated and press moldig at >=1,700 deg.C in a graphite container having desired inside form in a vacuum, and the resulting molding is rapidly cooled. The quartz glass may contain 10ppm-10wt% one or more among Ge, Ti, Al, Fe, F, P, Sn, Zn, Ca and B. The container has the structure of a split mold splittable into two or more, and the inside of the container is preferably coated with alpha- or beta-silicon carbide in 10-1,000mum thickness. |
