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:
Jan. 26, 1982
Filed:
Mar. 17, 1980
Jacques P Guertin, Cupertino, CA (US);
McGraw-Edison Company, Rolling Meadows, IL (US);
Abstract
A recrystallized copper billet in excess of one and one-half inches in diameter is formed as an essentially single-grain or crystal copper. A high conductivity, oxygen-free copper billet is subjected to mechanical surface cleaning and to a 'bright dip' bath to chemically clean the surface. The copper billet is located in a similar sized graphite crucible and induction-heated in a vacuum chamber to a modest temperature for outgassing of said crucible. The heating is increased to melt the copper and then is reduced in steps to produce a copper equilibrium temperature about seventeen degrees centigrade above the melting point of the copper. A slow non-directional and natural cooling at the rate of about three to fifteen degrees per hour is created until total solidification and recrystallization occurs.