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:
Sep. 01, 1992
Filed:
Dec. 20, 1990
Applicant:
Inventors:
Assignee:
Ishihara Sangyo Kaisha, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B22F / ;
U.S. Cl.
CPC ...
75349 ; 148105 ;
Abstract
The present invention provides a process for producing magnetic metal powder for magnetic recording using a metal compound mainly composed of a hydrous iron oxide on an iron oxide, characterized in that prior to subjecting the metal compound mainly composed of a hydrous iron oxide or an iron oxide to a reduction treatment, addition of a boron compound and a heat treatment at 350.degree.-750.degree. C. in a gas atmosphere having a water vapor partial pressure of 10 mmHg or higher are carried out. When a heat treatment at 550.degree.-900.degree. C. in a non-reducing atmosphere is carried out in combination with the above heat treatment, the effect of the present invention is further increased.