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:
Sep. 08, 1992
Filed:
Oct. 22, 1990
Johann Daimer, Oberahrain, DE;
Hartmut Paschke, Ergolding, DE;
Schott Glaswerke, Mainz, DE;
Abstract
A glass sealant comprises a mixture of about 70-90% of a solder glass powder of a low-melting lead-borate glass with a transformation temperature of 330.degree. C. or lower, 1-20% by weight of cordierite powder, and 1-25% by weight of mullite powder, with the combined content of cordierite and mullite powder being from about 10-30%. The lead-borate glass comprises from about 82-88% by weight of PbO, 12-17% by weight of B.sub.2 O.sub.3, 0-1% by weight of SiO.sub.2, and 0-1% by weight of Al.sub.2 O.sub.3. Both the cordierite and mullite powder are preferably synthetically produced to reduce the .alpha.-radiation. The synthetically produced cordierite powder preferably still contains up to about 9% by weight of a non-crystalline vitreous phase. The grain size of the powders is preferably under 100 microns. This glass sealant has well-balanced properties relative to thermal expansion, melting temperature, dielectric constant, loss angle, mechanical strength, thermal shock resistance, and chemical resistance. It is particularly suitable as ceramic dual-line package solder (CERDIP) for sealing of aluminum oxide housings for integrated circuits.