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. 09, 2002
Filed:
Aug. 16, 2000
Shigenobu Sekine, Tokyo, JP;
Yuko Kawasaki, Tokyo, JP;
Yoshiki Kuwabara, Tokyo, JP;
Hiroji Sato, Tokyo, JP;
Minoru Narita, Tokyo, JP;
Kazushi Suzuki, Tokyo, JP;
Koichi Tono, Tokyo, JP;
Keiji Okada, Kamagaya, JP;
Kenji Sakaguchi, Tokyo, JP;
Mitsuhisa Hirata, Funabashi, JP;
Sanei Kasei Co., Ltd., Tokyo, JP;
Abstract
The method for preparation of sintered permanent magnets according to the present invention comprises the steps of: mixing fully fine powder of a crystalline mother alloy for permanent magnet containing a rare-earth element, Fe and B as the essential components with fine powder of zinc oxide, compaction molding the resulted mixture in the presence of a magnetic field, sintering the compacted mixture in vacuum to cause generation of oxygen and metallic zinc by thermal decomposition of the zinc oxide; segregation of a part of metallic component in the mother alloy at the boundary and inside of the mother alloy crystal; formation of amorphous metallic oxide by forced oxidation of the segregated metal with the generated oxygen; crystallization of the amorphous metallic oxide; formation of an epitaxial junction between the crystallized metallic oxide and the mother alloy crystal; and evaporation of the metallic zinc into the vacuum, and quenching the sintered compact.