| 摘要 |
PROBLEM TO BE SOLVED: To prevent dispersion of lamp properties by solely heating a different metal powder having higher melting point and smaller particle size than a metal powder in vacuum and then mixing the heated metal powder with the latter powder and heating the resultant powder mixture in vacuum. SOLUTION: In the case a metal powder is heated in vacuum, another metal powder, for example, tungsten W powder which can not be sintered at the heating temperature range is previously mixed. In this case, W with smaller particle size than that of a metal powder is used. That is, the particle size of the powder metal and metal for halogenation is made to be 30-200μm and the particle size of tungsten is made to be 3μm or smaller by carrying out a process to mix the metal powder to be sealed in an arc tube with the tungsten powder and heat the mixture in vacuum and a process to unitedly mold the powder metal and halogenated metal. Consequently, dispersion of the amounts of additives sealed in the arc tubes and the component ratios is extremely suppressed to low level, so that dispersion of lamp properties can be prevented.
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