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. 12, 1988
Filed:
Apr. 22, 1987
Applicant:
Inventors:
Assignee:
TDK Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428329 ; 252 6254 ; 427128 ; 428328 ; 428694 ; 428900 ;
Abstract
A magnetic recording medium, comprising a plastic base coated with a magnetic layer of a ferromagnetic powder dispersed in a resin binder, contains in the magnetic layer .alpha.-Al.sub.2 O.sub.3 particles with an average particle size of 0.1 to 0.3 .mu.m as determined by electron microscopy in an amount of more than 0.5% but less than 15% by weight on the basis of the ferromagnetic powder weight. The .alpha.-Al.sub.2 O.sub.3 particles have an .alpha.-transformation rate of at least 50%. The powder is produced by an organic alumina process.