| 摘要 |
PURPOSE:To improve the vibration resistance of a W filament to be obtained, by regulating the density of a W sintered compact to a value lower than the peak density at the time of manufacturing a filament for tungsten halogen lamp by subjecting a doped W sintered compact to forging and wire drawing. CONSTITUTION:After a doping agent, such as K, Si, and Al, is blended with powdered WO3, WO3 is reduced into W in a hydrogen-gas atmosphere so as to prepare a doping agent-bearing W powder. This powder is compacted and the resulting green compact is temporarily sintered in a hydrogen furnace of 1,200 deg.C, which is directly electrified and sintered by means of resistance heat. At this time, the density after sintering is controlled so that it is 95-100%, preferably 97-99.5% based on the peak density to be obtained. This sintered compact is subjected to forging and wire drawing so as to be formed into a doped W wire having aligned dope holes of 0.39mm diameter and >=60mum length, so that W filament for tungsten halogen lamp excellent in vibration resistance can be manufactured.
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