| 摘要 |
463,889. Glass manufacture. GENERAL ELECTRIC CO., Ltd. (Patent-Treuhand- Ges. f³r Elektrische Gl³hlampen) Jan. 24, 1936, Nos. 2285 and 7525. Drawings to Specification. [Class 56] [Also in Group XXXVI] An intermediate glass or vitreous body, for sealing a conductor of tungsten, molybdenum, or like metal into a quartz vessel, is composed of 65-95 per cent of silica, 4-20 per cent. of alumina, and 0-30 per cent. of an alkalineearth oxide, preferably calcium oxide or barium oxide or both together. Compositions of a number of glasses with their expansion co-efficients and softening temperatures are given in the Specification. The batch may be melted in a crucible of refractory metal, particularly of tungsten or molybdenum, the crucible being surrounded by a neutral or reducing atmosphere when these metals are used. Alternatively, the batch is not melted but is sintered to form a mass of the required shape. In this case, a crucible is not required, the batch being compressed in moulds, or formed into a slurry and cast in the required shape, and then heated until the material sinters into a coherent body which is preferably glazed, at least on one surface. The tungsten or molybdenum conductors may be placed in their proper positions in the shaped material before sintering, and the junction between the material and the metal conductor is heated so strongly that a vitreous layer is formed at the contact between them. Specification 2176/13, [Class 56], is referred to. |
