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:
Mar. 26, 2002
Filed:
Mar. 28, 2000
Yuji Kaneko, Uji, JP;
Junichiro Baba, Osaka, JP;
Kazuo Tanaka, Yokohama, JP;
Shizuo Mori, Yokohama, JP;
Sumitomo Special Metals Co., Ltd., Osaka, JP;
Abstract
The method of producing an R—Fe—B magnet of the present invention is characterized in that R—Fe—B alloy fine powder is molded in a magnetic field and sintered using a lubricant for molding magnets containing specific components, individually or as a mixture, of specific amounts of methyl caproate and/or methyl caprylate, which provide high crystal orientation, and lubricant comprising depolymerized polymer for improving molded article strength, or a lubricant for molding magnets wherein Ti coupling agent that improves crystal orientation is added to this lubricant for molding magnets. Each particle of the fine powder has a high degree of crystal orientation in the direction of the magnetic field, and molded article strength is markedly improved, leading to improved mass-productivity and yield. Moreover, the above-mentioned lubricants do not react with this magnet powder during sintering and are emitted as a gas. Therefore, binder removal performance is excellent and as a result, an increase in the amount of C remaining in the sintered compact is inhibited, to obtain an R—Fe—B permanent magnet with high Br and iHc properties.