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:
Oct. 22, 1985
Filed:
Jun. 08, 1984
Koichi Yoshida, Shizuoka, JP;
Yoshio Hirayama, Shizuoka, JP;
Yasuo Oka, Shizuoka, JP;
Takashi Kajiyama, Shizuoka, JP;
Nippon Light Metal Company Limited, Tokyo, JP;
Abstract
A magnetic recording medium having excellent magnetic properties and a uniform recording envelope suitable for, in particular, high-density recording is obtained by packing a magnetic substance in the micro pores of anodic oxide film formed on an aluminum substrate by subjecting the same to an anodic oxidation treatment to produce an anodic oxide film having a thickness of at least 4 .mu.m. The recording medium can be improved by immersing the anodized aluminum substrate in an acid or alkali bath to chemically dissolve a part of the anodic oxide film, and thereby enlarge the micro pores in the anodic oxide film to a pore diameter in the range of 300 .ANG. to 1,400 .ANG., optionally applying an electric current to the aluminum substrate in the immersion bath if necessary to control the thickness of the barrier layer in the anodic oxide film, before subjecting the treated substrate to an electrolytic treatment in a bath containing ions of a magnetic substance to deposit the magnetic substance in the enlarged micro pores. Thereafter, the surface of the anodic oxide film, and any excess deposited magnetic material thereon, is physically ground to expose the packed magnetic substance at the surface of the film.