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:
Jul. 07, 1987
Filed:
Sep. 04, 1986
Applicant:
Inventors:
Assignee:
Furukawa Aluminum Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
C25D / ;
U.S. Cl.
CPC ...
204 371 ; 204 351 ; 204 58 ; 365 97 ; 365171 ; 369288 ; 428545 ; 428934 ;
Abstract
An anodized memory disk substrate is disclosed, which is characterized in having an anodic film having excellent heat resistance and hardness and having a thickness of not less than 3 .mu.m on the surface of aluminum or an aluminum alloy substrate imparted thereto by means of chromic acid-sulfuric acid mixture. The method described therefor is that, after the formation of anodic film having a film thickness of not less than 4 .mu.m on the surface of substrate, polishing is carried out so as to leave behind the anodic film having a film thickness of at least 3 .mu.m. Heat treatment may be made before or after the polishing.