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:
Mar. 24, 1992
Filed:
Mar. 25, 1991
Lifun Lin, Waltham, MA (US);
Chung-Yao Chao, Waltham, MA (US);
Olin Corporation, New Haven, CT (US);
Abstract
A technique for improving the tarnish and oxidation resistance of copper and copper based alloy materials is disclosed. Copper or a copper alloy is immersed in an aqueous solution containing sodium hydroxide, zinc ions and chromium (VI) ions. While the compositional ranges may vary, the concentration of either zinc ions or chromium (VI) ions, or both, is less than 1.0 gm/1. A chromium-zinc coating is electrolytically applied. The coating provides tarnish resistance at temperatures in excess of 190.degree. C. The coating is removable by immerison in sulfuric acid. Improved results are obtained by rinsing deionized water containing a small amount of an alkaline or alkaline earth hydroxide.