| 摘要 |
483,772. Glass manufacture. GENERAL ELECTRIC CO., Ltd. (Patent-Treuhand-Ges. f³r Elektrische Gl³hlampen) March 1, 1937, No. 6064. [Class 56] A glass which resists attack by alkali metal vapours contains 20-30 per cent of B2O3, 20-30 per cent of Al2O3, 4-9 per cent of SiO2, 30-40 per cent of alkaline earths, and 6-10 per cent of alkalies. The envelope of an electric discharge tube containing alkali metal vapour may consist of the resistant glass flashed on to the surface of a soft soda glass, of well known kind, composed of 65À5 per cent of SiO2, 2 per cent of Al2O3, 1 per cent of K2O, 16À5 per cent of Na2O, 5À5 per cent of CaO, 3À5 per cent of MgO2 and 2 per cent of BaO. |
