| 摘要 |
PROBLEM TO BE SOLVED: To provide a niobium feedthrough for ceramic discharge vessels having greater oxidation resistance, a method of making a seal in a ceramic discharge vessel, and an HID discharge lamp with a ceramic discharge vessel operating in an open-air fixture without an outer jacket. SOLUTION: A light source 30 includes an open-air fixture 32, a discharge tube 10 includes a tubular body 12 formed of polycrystalline alumina, and a seal 14 includes a sub-assembly 26 that includes an annular polycrystalline alumina disc 18, the outer surface 20 of which is bonded to the body 12. A tubular niobium feedthrough 22 is sealed to the inner surface of the annular disc 18, that is, the surface 24. The tubular niobium feedthrough 22 has a layer 28 formed of chromium or an alloy of chromium and niobium that is bonded to its external surface. By altering the niobium feedthrough with the chromium layer, the layer 28 becomes resistant to oxidation, thus permitting open-air operation. COPYRIGHT: (C)2009,JPO&INPIT
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