| 摘要 |
PURPOSE:To permit easy and low cost mass-production of the high-pressure sodium lamps which are suitable for a relatively low wattage and possess an equal quality by using the material comprising the metal powder having a high melting point, tungstate and carbonate of alkaline-earth metals as main components of sintered electrode, adding boron compounds of rare-earth metals, and molding and sintering said materials. CONSTITUTION:Rare gas such as xenone gas is sealed-up together with a proper amount of sodium and mercury in a luminous bulb. Sintered electrode 6, 7 has the structure in which a sintered body 9 is fixed at the top of the electrode center rod 8 made of the metal having a high melting point such as tungsten. The ratio of each component by weight is 75-85% tungsten powder, 15-23% barium/calcium tungstate, 1-5% barium carbonate, and 1-5% lanthanum hexaborate. The above compounds are mixed well through adding binder, and pressurized and molded, and then sintered in a hydrogen gas atmosphere at a high temperature. |
