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US 4,545,799 AGranted
Method of making direct seal between niobium and ceramics
AssigneesGTE Laboratories Incorporated, GTE Products Corporation
InventorsWilliam H. Rhodes, Caryl S. Pitt, John J. Gutta
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Abstract
A high pressure arc lamp has a ceramic arc tube envelope. A niobium feedthrough positions electrodes within the tube. A ceramic insert at each end of the tube forms a direct high temperature hermetic seal with the niobium feedthrough and the ceramic tube without the use of frits or brazing.
Claims1
A method of making a tube assembly for a high pressure discharge lamp comprised of the steps of:
- a. providing a tube made of unsintered compressed ceramic powder
- b. providing a niobium feedthrough;
- c. providing an insert made of unsintered compressed ceramic powder having a similar thermal expansion coefficient as that of said tube, said insert in the shape of a disc with an axial hole;
- d. inserting said unsintered insert in an end of the unsintered tube;
- e. heating said insert and tube until both are partially sintered and bonded together;
- f. positioning said niobium feedthrough in the axial hole of said insert;
- and
- g. heating said tube, insert and niobium feedthrough until said tube and insert are fully sintered and said insert is contracted and forced against said niobium feedthrough, forming thereby a brazeless, fritless hermetic seal at the interface between said insert and said niobium feedthrough.
5 more elements
Dependencies are inferred from the claim text.