| 摘要 |
465,077. Glass manufacture. GENERAL ELECTRIC CO., Ltd. (Patent - Treuhand- Ges. f³r Elektrische Gl³hlampen) March 10, 1936, No. 7223. [Class 56] A glass which resists attack by metal vapours is composed of 15-25 per cent of silica, 25- 35 per cent of alumina, and 20-35 per cent of boron trioxide, the remainder consisting of calcium oxide or barium oxide or both together. The glass is suitable for use in making the envelopes of electric discharge lamps containing the vapour of sodium, potassium, or magnesium. An envelope may be made entirely of the glass, or it may be made of any other suitable glass which is flashed on its inner surface with a coating of glass having the composition given above. |
