| 摘要 |
1,140,227. Metal-ceramic seals. PATENTTREUHAND GES. FœR ELEKTRISCHE GLœHLAMPEN m.b.H. 11 March, 1966 [11 March, 1965], No. 10782/66. Heading B3V. An electric lamp, e.g. an alkalimetal vapour discharge lamp comprises an envelope 1 of transparent sintered alumina the ends of which are each fused to a ceramic closure or one of metal 4, 5 having a ceramic layer 2, 3 against the envelope, the ceramic closure, or the ceramic layer, or at least the portion thereof adjacent the envelope being composed of at least 90% by weight of aluminium oxide and a maximum of 10% of another metal oxide, such that the composition has a eutectic point above 1700‹ C. and below that of the alumina of the envelope. The other oxide may be magnesium oxide below 5% by weight, e.g. 2%, thus lowering the m.p. by more than 100‹ C. Additions of beryllium oxide of less than 10%, e.g. 7%, lower the m.p. by more than 200‹ C. End closures of niobium may be fused to the transparent alumina envelope 1 during a fusion period of one to two minutes at 1900‹ C. Electrodes 6 and 7 pass through the seals. |
