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. 06, 2005
Filed:
Oct. 10, 2002
Masashi Aonuma, Kanagawa, JP;
Masashi Aonuma, Kanagawa, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A ferromagnetic metal powder having an average long axis length of from 30 to 65 nm, a crystallite size of from 80 to 130 angstroms, a saturation magnetization (σs) of from 75 to 130 A·m/kg, and an average oxide layer thickness of from 1.5 to 2.5 nm; a method of producing a ferromagnetic metal powder comprising: reducing the oxide of a ferromagnetic metal element to obtain the ferromagnetic metal powder, subjecting the ferromagnetic metal powder to gradual oxidation treatment to make as 120 to 150 A·m/kg, adhering at least one element selected from Al, Y, lanthanoid, Zr and W to the ferromagnetic metal powder in water, performing heat treatment, and again performing gradual oxidation treatment; and a magnetic recording medium comprising a support having provided thereon a magnetic layer mainly comprising a ferromagnetic metal powder and a binder, wherein the magnetic layer containing the ferromagnetic metal powder has a thickness of from 0.04 to 0.25 μm, and demagnetization after storage at 60° C. 90% RH for one week of 10% or less.