Invention Application
- Patent Title: R-T-B BASED SINTERED MAGNET
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Application No.: US15939719Application Date: 2018-03-29
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Publication No.: US20180301256A1Publication Date: 2018-10-18
- Inventor: Yoshinori FUJIKAWA , Masashi MIWA
- Applicant: TDK CORPORATION
- Applicant Address: JP Tokyo
- Assignee: TDK CORPORATION
- Current Assignee: TDK CORPORATION
- Current Assignee Address: JP Tokyo
- Priority: JP2017-069147 20170330; JP2018-055201 20180322
- Main IPC: H01F1/057
- IPC: H01F1/057 ; C22C38/00 ; C22C38/10 ; C22C38/16 ; C22C38/14 ; C22C38/06

Abstract:
An R-T-B based sintered magnet including main phase particles having an R2T14B type crystal structure. R is at least one rare earth element essentially including a heavy rare-earth element RH. T is at least one transition metal element essentially including Fe or Fe and Co. B is boron. At least one of the main phase particles includes low RH crystal phases inside the main phase particle. The low RH crystal phases include the R2T14B type crystal structure, wherein an RH concentration in the low RH crystal phases is relatively lower than the RH concentration in the whole main phase particles. The R-T-B based sintered magnet may satisfy rs−rc≥20% when an existence ratio of the main phase particles including the low RH crystal phases in a magnet surface layer part is rs (%) and the same in a magnet central part is rc (%).
Public/Granted literature
- US10748685B2 R-T-B based sintered magnet Public/Granted day:2020-08-18
Information query
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