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:
Jan. 23, 2007
Filed:
Dec. 03, 2004
Kazuyuki Matsumoto, Okayama, JP;
Kimitaka Sato, Okayama, JP;
Takatoshi Fujino, Honjo, JP;
Kenichi Inoue, Okayama, JP;
Kazuyuki Matsumoto, Okayama, JP;
Kimitaka Sato, Okayama, JP;
Takatoshi Fujino, Honjo, JP;
Kenichi Inoue, Okayama, JP;
Dowa Mining Co., Ltd., Tokyo, JP;
Abstract
A ferromagnetic iron alloy powder for a magnetic recording medium is composed of acicular iron-base particles of an average major axis length (X) of not less than 20 nm and not greater than 80 nm and have oxygen content of not less than 15 wt % and coercive force (Hc) of not less than [0.0036 X−1.1 X+110 X−1390 (Oe)] (where X is average major axis length expressed in nm). The ferromagnetic iron alloy powder is obtained by reacting metal powder composed of acicular iron-base particles having an average major axis length of not less than 20 nm and not greater than 80 nm with pure water in substantial absence of oxygen to form a metal oxide film on the particle surfaces. Optionally, the particles can be reacted with a weak oxidizing gas by a wet or dry method.