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:
Apr. 07, 1998
Filed:
Mar. 07, 1996
Jean A Lown, St. Paul, MN (US);
Yasutaka Ota, Hiroshima, JP;
Kenji Okinaka, Hiroshima, JP;
Hirofumi Kawasaki, Hiroshima, JP;
Imation Corp., Oakdale, MN (US);
Toda Kogyo Corp., Hiroshima, JP;
Abstract
The present invention is a method for making highly stable magnetic alloy particles with high coercivities and high saturation magnetization comprising the steps of: a) providing a precursor selected from the group consisting of iron oxide hydroxide particles and iron oxide particles, wherein the precursor particle comprises from about 15 to about 45 atomic % Co based on amount of Fe present, b) reducing the precursor particles to magnetic alloy particles, c) passivating the magnetic alloy particles in an oxygen-containing atmosphere at a temperature between about 20.degree. and 100.degree. C., d) annealing the passivated magnetic alloy particles in an inert atmosphere at a temperature from about 120.degree. to about 450.degree. C., and e) further oxidizing the annealed magnetic alloy particles in an oxygen-containing atmosphere.