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. 23, 1982
Filed:
Apr. 24, 1980
Applicant:
Inventors:
Shinji Umeki, Tokyo, JP;
Toshihiro Hamabata, Tokyo, JP;
Kazuaki Onuki, Tokyo, JP;
Kazuo Takada, Tokyo, JP;
Assignee:
TDK Electronics Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
C01G / ; C01G / ;
U.S. Cl.
CPC ...
428404 ; 427127 ; 252 6256 ; 252 6259 ; 428693 ;
Abstract
A magnetic iron oxide powder having high coercive force is produced by dispersing a magnetic iron oxide comprising a silicon component and a phosphorus component in an aqueous solution of a cobalt ion and adding a base to the dispersion to be an alkaline condition and heat-treating the dispersion whereby the cobalt ion is adsorbed and diffused in the surface layer of the magnetic iron oxide. A zinc component can be also incorporated in the crystal. The silicon component and the phosphorus component are preferably incorporated in the crystalline structure.