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. 27, 1976
Filed:
Mar. 28, 1974
Applicant:
Inventors:
Shiro Terai, Nagoya, JA;
Akinari Ichiryu, Aichi, JA;
Toshio Suzuki, Kasugai, JA;
Yoshikatsu Hayashi, Nagoya, JA;
Assignee:
Sumitomo Light Metal Industries, Ltd., Tokyo, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C25D / ;
U.S. Cl.
CPC ...
204 58 ; 25D / ;
Abstract
A colored oxide film on the surface of aluminium or an alloy thereof can be formed by anodizing at a D.C. voltage in an electrolyte based on sulfuric acid, followed by alternating current electrolysis at an A.C. voltage which is lower than the D.C. voltage. In order to increase the degree of coloring of the colored oxide film, after the alternating current electrolysis the A.C. voltage is raised to a higher level but lower than the D.C. voltage, followed by dropping the voltage down to a level of the A.C. voltage or thereabout.