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US 5,725,827 AGranted
Sealing members for alumina arc tubes and method of making same
AssigneeOsram Sylvania Inc.
InventorsWilliam H. Rhodes, Alfred E. Feuersanger, Rodrigue Thibodeau
Life of this patent
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Abstract
Alumina arc tube sealing members including a highly pure, fine alumina doped with yttrium oxide, and magnesium oxide. The sealing members are used in the formation of sintered hermetic seals to a green, prefired, or fully sintered translucent alumina arc tube and niobium electrical feedthrough assemblies with or without the use of sealing frits or brazing alloys.
Claims9
A process comprising:
- preparing a homogeneous powdery mixture consisting essentially of highly pure fine alumina having a particle size suitable for sintering, at least one component selected from the group consisting of yttrium oxide and yttrium compounds capable of being converted to yttrium oxide by calcination in an oxidizing atmosphere, the amount of said yttrium oxide being between greater than about 1.0 to about 5.0 percent by weight, and at least one other component selected from the group consisting of magnesium oxide and magnesium compounds capable of being converted to magnesium oxide by calcination in an oxidizing atmosphere, the amount of said magnesium oxide being between about 0.05 to about 0.1 percent by weight;
- forming a sealing member for alumina are tubes from said mixture;
- and
- sealing said alumina arc tube with said sealing member at a temperature between about 1640.degree. C. to about 2050.degree. C. for a period of time sufficient to obtain a long life, high density, hermetically tight sintered seal.
1 more element
Dependencies are inferred from the claim text.