| 摘要 |
783,244. Glass manufacture. QUARTZ & SILICE. March 5, 1956 [March 5, 1955], No. 6830/56. Drawings to Specification. Class 56. In the manufacture of silica glass, the very pure glass, in substantially its final shape, is subjected to the action of a continuous electrical field at high temperature. In this way, the silica glass loses all fluorescence and an absorption band of ultra violet rays in the region of 2450 AU is removed. In order to remove an absorption band of infra red rays in the region of 2À75 u, the silica glass is obtained from primary materials not containing any OH ions and the melting is carried out by any suitable means other than flames. Preferably the primary materials are reduced to very fine particles, e.g. powders formed by the oxidation of organic compounds of silicon. The shaped article is then placed between metallic electrodes and the assembly placed in a furnace and raised to a temperature of about 1000‹C. for about 30 hours, while a continuous field of 1000 volt/cms. is applied between the electrodes for the same period, producing a very thin layer of quartz or cristobalite which is then removed. |
