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:
Feb. 20, 2007
Filed:
Oct. 17, 2003
Yasuyoshi Suzuki, Chiryu, JP;
Yurio Nomura, Nagoya, JP;
Yoshiaki Nishijima, Toyokawa, JP;
Shoji Miyake, Suita, JP;
Yukio Makino, Nishinomiya, JP;
Teppei Satoh, Mino, JP;
Yasuyoshi Suzuki, Chiryu, JP;
Yurio Nomura, Nagoya, JP;
Yoshiaki Nishijima, Toyokawa, JP;
Shoji Miyake, Suita, JP;
Yukio Makino, Nishinomiya, JP;
Teppei Satoh, Mino, JP;
Denso Corporation, Kariya, JP;
Abstract
The invention provides a method for preparing a soft magnetic material which meets demands for low iron loss, high density, high strength and high productivity. The method comprises a surface oxidation step of forming oxide films on the surfaces of a soft magnetic powder, a step of preparing a molding compound of the soft magnetic powder by mixing a soft magnetic powder and a binder with a predetermined blending ratio, a press molding step of press-molding the molding compound of the soft magnetic powder into a predetermined shape, and a sintering step of sintering the press-molded soft magnetic powder to produce a soft magnetic material, wherein a millimeter wave sintering apparatus or a discharge plasma sintering apparatus is used as a heating means in the surface oxidation step or in the sintering step. Thereby, energy of millimeter waves or discharge plasma acts locally on oxidized surface portions having a large electric resistance of the soft magnetic powder, the surfaces of the soft magnetic powder are locally heated at a temperature near the melting point, and oxidation of the surfaces of the soft magnetic powder (formation of an oxide film) and sintering (diffusional joining between oxide films) are promoted.