The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 07, 1990
Filed:
Aug. 09, 1988
William D Hepburn, Edinburgh, GB;
Ferranti International Signal, plc, Cheshire, GB;
Abstract
A seal between two ceramic articles, or between a ceramic article and a metal article, is formed by providing a sealing member comprising an aluminum body, and a film of zinc or tin being deposited threon, with the inevitable aluminum oxide surface film removed, and subsequently a coating of silver and/or gold, or a suitable alloy containing silver or gold, being provided. The sealing member is positioned between the articles, and the bonding operation comprises heating the assembly in an inert atmosphere, or in a high vacuum, to melt the composite sealing member, there being obviated the need to apply pressure during the bonding operation. Any oxide film on silver readily decomposes at a temperature of, at most, 250.degree. C. No oxide film is formed on gold. The zinc or tin film, and the coating, are readily absorbed into the molten aluminum produced during the bonding operation. Subsequently, the bonded assembly is out-gassed at a temperature up to 600.degree. C. A ceramic article may be of a glass ceramic, or of fused silica; and a metal article may be of a suitable nickel-iron alloy.