Invention Grant
- Patent Title: R-T-B sintered magnet
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Application No.: US13980133Application Date: 2012-01-19
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Publication No.: US09837193B2Publication Date: 2017-12-05
- Inventor: Futoshi Kuniyoshi
- Applicant: Futoshi Kuniyoshi
- Applicant Address: JP Tokyo
- Assignee: HITACHI METALS, LTD.
- Current Assignee: HITACHI METALS, LTD.
- Current Assignee Address: JP Tokyo
- Agency: Keating & Bennett, LLP
- Priority: JP2011-008434 20110119
- International Application: PCT/JP2012/051038 WO 20120119
- International Announcement: WO2012/099188 WO 20120726
- Main IPC: H01F1/053
- IPC: H01F1/053 ; B22F3/24 ; C22C33/02 ; C22C38/00 ; H01F41/02 ; H01F1/057

Abstract:
This sintered R-T-B based rare-earth magnet includes: R2Fe14B type compound crystal grains, including a light rare-earth element RL (which includes at least one of Nd and Pr) as a major rare-earth element R, as main phases; and a heavy rare-earth element RH (which includes at least one of Dy and Tb). Before its surface region is removed, the sintered R-T-B based rare-earth magnet has no layer including the rare-earth element R at a high concentration in that surface region. The sintered R-T-B based rare-earth magnet has a portion in which coercivity decreases gradually from its surface region toward its core portion. The difference in the amount of TRE between a portion of the sintered R-T-B based rare-earth magnet that reaches a depth of 500 μm as measured from its surface region toward its core portion and the core portion of the sintered R-T-B based rare-earth magnet is 0.1 through 1.0.
Public/Granted literature
- US20130293328A1 R-T-B SINTERED MAGNET Public/Granted day:2013-11-07
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