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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.:

US 10566117 B1

PDFFull Text
Date of Patent:
Feb. 18, 2020

Filed:

Jul. 13, 2017

R-t-b based rare earth permanent magnet

Applicant:

Tdk Corporation, Tokyo, JP;

Inventors:

Keiji Takeda, Tokyo, JP;

Shota Miyazaki, Tokyo, JP;

Assignee:

TDK CORPORATION, Tokyo, JP;

Attorney:

Oliff PLC

Primary Examiner:

Xiaowei Su

Int. Cl.
CPC ...
H01F 1/057 (2006.01); B22F 3/24 (2006.01); B22F 3/16 (2006.01); C22C 38/00 (2006.01); H01F 7/02 (2006.01); C22C 38/10 (2006.01); C22C 38/06 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); B22F 3/02 (2006.01); B22F 1/00 (2006.01); B22F 9/04 (2006.01); B22F 3/10 (2006.01); B22F 9/02 (2006.01);
U.S. Cl.
CPC ...
H01F 1/0577 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/06 (2013.01); C22C 38/10 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); H01F 7/02 (2013.01); B22F 1/0011 (2013.01); B22F 3/02 (2013.01); B22F 3/10 (2013.01); B22F 9/023 (2013.01); B22F 2003/248 (2013.01); B22F 2009/044 (2013.01); B22F 2009/048 (2013.01); B22F 2998/10 (2013.01); B22F 2999/00 (2013.01); C22C 2202/02 (2013.01);
Abstract

An R-T-B based rare earth permanent magnet is expressed by a compositional formula: (R11−x(Y1−y−z Cey Laz)x)aTbBcMd in which R1 is one or more kinds of rare earth element not including Y, Ce and La, 'T' is one or more kinds of transition metal, and includes Fe or Fe and Co as an essential component, 'M' is an element having Ga or Ga and one or more kinds selected from Sn, Bi and Si, and 0.4≤x≤0.7, 0.00≤y+z≤0.20, 0.16≤a/b≤0.28, 0.050≤c/b≤0.075 and 0.005≤d/b≤0.028. The magnet includes a main phase, including a compound having a R2T14B type tetragonal structure, and a grain boundary phase. D10, D50, D90 of crystal grain diameter according to the main phase crystal grains satisfies the following formula: D50≤4.00 μm and (D90−D10)/D50≤1.60. A coating rate of the grain boundary is 70.0% or more.

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