Rare-earth permanent magnet

Patent metadata

Field	Value
Publication number	US-2017047151-A1
Application number	US-201515304193-A
Country	US
Kind code	A1
Filing date	Mar 10, 2015
Priority date	Apr 15, 2014
Publication date	Feb 16, 2017
Grant date	—

Abstract

To provide a permanent magnet which uses Ce of an abundant resource and has a great magnetic anisotropy in rare earth permanent magnets. To obtain a permanent magnet having a high magnetic anisotropy due to the trivalent Ce state by setting the abundance ratio C3/(C3+C4) in the main phase grains to be 0.1≦C3/(C3+C4)≦0.5 where C3 denotes the number of trivalent Ce atoms and C4 denotes the number of tetravalent Ce atoms.

First claim

1 . A rare earth permanent magnet comprising main phase grains, wherein an abundance ratio C3/(C3+C4) in the main phase grains is 0.1≦C3/(C3+C4)≦0.5, where C3 denotes the number of trivalent Ce atoms and C4 denotes the number of tetravalent Ce atoms in the main phase grains.

2 . The rare earth permanent magnet according to claim 1 , wherein the main phase grains comprise an R-T-X compound having a Nd 2 Fe 14 B type crystal structure (space group P4 2 /mnm), where
“R” represents one or more kinds of rare earth elements including Ce or including Ce and Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, “T” represents one or more kinds of transition metal elements including Fe or Fe and Co, and “X” represents B or B and an element of Be, C, or Si that substitutes part of B.

3 . The rare earth permanent magnet according to claim 1 , wherein the main phase grains comprise an R-T compound having a TbCu 7 type crystal structure (space group P6/mmm), where
“R” represents one or more kinds of rare earth elements including Ce or including Ce and Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu and “T” represents one or more kinds of transition metal elements including Fe or Fe and Co.

4 . The rare earth permanent magnet according to claim 3 , wherein the main phase grains further contain an interstitial element “X” (“X” represents one or more elements of N, H, Be, and C).

5 . The rare earth permanent magnet according to claim 3 , wherein “R” is partially substituted with Zr in the main phase grains.

6 . The rare earth permanent magnet according to claim 1 , wherein the main phase grains comprise an R-T compound having a ThMn 12 type crystal structure (space group I4/mmm), where
“R” represents one or more kinds of rare earth elements including Ce or including Ce and Y, La, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, and Lu and “T” represents one or more kinds of transition metal elements including Fe or Fe and Co or represents the transition metal elements partially substituted with “M” (“M” represents one or more kinds of Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, Zn, Ga, and Ge).

7 . The rare earth permanent magnet according to claim 6 , wherein the main phase grains further contain an interstitial element “X” (“X” represents one or more kinds of elements of N, H, Be, and C).

8 . The rare earth permanent magnet according to claim 1 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

9 . The rare earth permanent magnet according to claim 4 , wherein “R” is partially substituted with Zr in the main phase grains.

10 . The rare earth permanent magnet according to claim 2 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

11 . The rare earth permanent magnet according to claim 3 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

12 . The rare earth permanent magnet according to claim 4 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

13 . The rare earth permanent magnet according to claim 5 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

14 . The rare earth permanent magnet according to claim 6 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

15 . The rare earth permanent magnet according to claim 7 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

16 . The rare earth permanent magnet according to claim 9 , wherein the abundance ratio of the number of trivalent Ce atoms and the number of tetravalent Ce atoms in the main phase grains is calculated from an electron energy loss spectrum.

Assignees

• Tdk Corp

Inventors

• Kadota Shogo
• Suzuki Kenichi
• Umeda Yuji
• Hashimoto Ryuji
• Takeda Keiji

Classifications

• H01F1/057 Primary

  and IIIa elements, e.g. Nd2Fe14B · CPC title

• H01F1/0556

  pressed · CPC title

• H01F1/058

  and IVa elements, e.g. Gd2Fe14C · CPC title

• C22C38/005

  containing rare earths, i.e. Sc, Y, Lanthanides · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title