公开(公告)号：US20180019043A1

公开(公告)日：2018-01-18

申请号：US15643956

申请日：2017-07-07

Applicant: TDK CORPORATION

Inventor： Koji MIURA ,  Ryoma NAKAZAWA ,  Katsushi YASUHARA ,  Tomohisa MITOSE

IPC: H01F1/147 ,  C22C38/10 ,  B22F9/08 ,  H01F3/08 ,  C22C38/02

CPC classification number: H01F1/14766 ,  B22F9/082 ,  B22F2001/0066 ,  B22F2301/35 ,  B22F2304/10 ,  B22F2998/10 ,  C22C1/05 ,  C22C33/0264 ,  C22C33/0285 ,  C22C38/02 ,  C22C38/10 ,  C22C2202/02 ,  H01F3/08 ,  B22F2003/023

Abstract: A soft magnetic metal powder includes a plurality of soft magnetic metal particles composed of an Fe—Co based alloy. The Fe—Co based alloy includes 0.50 mass % or more and 8.00 mass % or less of Co and a remaining part composed of Fe and an inevitable impurity. A soft magnetic metal powder includes a plurality of soft magnetic metal particles composed of an Fe—Co based alloy. The Fe—Co based alloy includes 0.50 mass % or more and 8.00 mass % or less of Co, 0.01 mass % or more and 8.00 mass % or less of Si, and a remaining part composed of Fe and an inevitable impurity. The present invention can provide a soft magnetic metal powder or so having a favorable corrosion resistance.

公开(公告)号：US20210313099A1

公开(公告)日：2021-10-07

申请号：US17202410

申请日：2021-03-16

Applicant: TDK Corporation

Inventor： Masashi MIWA ,  Koji MIURA ,  Taeko TSUBOKURA

IPC: H01F1/057 ,  C22C28/00 ,  B22F3/16 ,  B22F9/04

Abstract: Provided is a permanent magnet including a rare-earth element R (such as Nd), a transition metal element T (such as Fe), B, Zr, and Cu. The permanent magnet contains a plurality of main phase grains including Nd, T, and B, and grain boundary multiple junctions, the one grain boundary multiple junction is a grain boundary surrounded by three or more of the main phase grains, one of the grain boundary multiple junctions contains a ZrB2 crystal and an R—Cu-rich phase including R and Cu, a concentration of B in the one grain boundary multiple junction containing both the ZrB2 crystal and the R—Cu-rich phase is from 5 to 20 atomic %, a concentration of Cu in the one grain boundary multiple junction containing both the ZrB2 crystal and the R—Cu-rich phase is from 5 to 25 atomic %, and a surface layer part of the main phase grain includes at least one kind of heavy rare-earth element among Tb and Dy.

公开(公告)号：US20210304929A1

公开(公告)日：2021-09-30

申请号：US17202424

申请日：2021-03-16

Applicant: TDK Corporation

Inventor： Masashi MIWA ,  Yoshitomo TANAKA ,  Koji MIURA ,  Taeko TSUBOKURA

IPC: H01F1/057 ,  C22C38/00 ,  C22C38/16 ,  C22C38/10 ,  C22C38/06 ,  C22C38/14

Abstract: Provided is a permanent magnet including a rare-earth element R (such as Nd), a transition metal element T (such as Fe), B, Zr, and Cu. The permanent magnet contains a plurality of main phase grains including Nd, T, and B, and grain boundary multiple junctions, the one grain boundary multiple junction is a grain boundary surrounded by three or more of the main phase grains, one of the grain boundary multiple junctions contains a ZrB2 crystal and an R—Cu-rich phase including R and Cu, Fe is contained in the ZrB2 crystal, a total concentration of Nd and Pr in the one grain boundary multiple junction containing both the ZrB2 crystal and the R—Cu-rich phase is higher than a total concentration of Nd and Pr in the main phase grain, a concentration of Cu in the one grain boundary multiple junction containing both the ZrB2 crystal and the R—Cu-rich phase is higher than a concentration of Cu in the main phase grain, and a unit of the concentration of each of Nd, Pr, and Cu is atomic %.

公开(公告)号：US20210407714A1

公开(公告)日：2021-12-30

申请号：US17356178

申请日：2021-06-23

Applicant: TDK CORPORATION

Inventor： Koji MIURA ,  Masashi MIWA

IPC: H01F1/057 ,  C22C38/00

Abstract: To provide an R-T-B based permanent magnet having a high residual magnetic flux density Br at room temperature and a high coercivity HcJ at high temperature. In the R-T-B based permanent magnet, R is a rare earth element, T is an iron group element, and B is boron, and the R-T-B based permanent magnet includes a light rare earth element and a heavy rare earth element as R. The R-T-B based permanent magnet further includes Al, Ga, and Zr. With respect to 100 mass % of the R-T-B based permanent magnet, a total content of R is 28.50 mass % to 30.25 mass % (not including 28.50 mass %), B content is 0.93 mass % to 0.98 mass %, Al content is 0.03 mass % to 0.19 mass %, Ga content is 0.03 mass % to 0.15 mass %, and Zr content is 0.30 mass % to 0.50 mass %.