Rare-earth magnet and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-10748684-B2
Application number	US-201916532651-A
Country	US
Kind code	B2
Filing date	Aug 6, 2019
Priority date	Jun 5, 2013
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

To provide a rare earth magnet ensuring excellent magnetic anisotropy while reducing the amount of Nd, etc., and a manufacturing method thereof.
A rare earth magnet comprising a crystal grain having an overall composition of (R2 (1-x) R1 x ) y Fe 100-y-w-z-v Co w B z TM v (wherein R2 is at least one of Nd, Pr, Dy and Tb, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x<1, y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2), wherein the average grain size of the crystal grain is 1,000 nm or less, the crystal grain consists of a core and an outer shell, the core has a composition of R1 that is richer than R2, and the outer shell has a composition of R2 that is richer than R1.

First claim

The invention claimed is:

1. A method for manufacturing a rare earth magnet, comprising:
a first step of performing hot pressing by using a magnetic powder having a composition of (R2 (1-x) R1 x ) y Fe 100-y-y-w-z-v Co w B z TM v , wherein R2 is at least one of Nd and Pr, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x≤1 in molar ratio, and y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2, in molar percentage; to produce a rare earth magnet precursor, and
a second step of diffusing and impregnating a modifying metal composed of an R2 element or an R2-TM alloy into the rare earth magnet precursor to manufacture a rare earth magnet comprising a crystal grain having an average grain size of 1,000 nm or less and consisting of a core and an outer shell, the core having a composition of R1 that is richer than R2, or a composition in which the concentrations of R1 and R2 are the same and the outer shell having a composition of R2 that is richer than R1.

2. A method for manufacturing a rare earth magnet, comprising:
a first step of performing hot pressing by using a magnetic powder having a composition of (R2 (1-x) R1 x ) y Fe 100-y-y-w-z-v Co w B z TM v , wherein R2 is at least one of Nd and Pr, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x≤1 in molar ratio, and y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2, in molar percentage to produce a rare earth magnet precursor, and
a second step of diffusing and impregnating a modifying metal composed of an R2 element or an R2-TM alloy into the rare earth magnet precursor to manufacture a rare earth magnet comprising a crystal grain having an average grain size of 1,000 nm or less, consisting of a core and an outer shell, and having a composition of R1/(R2+R1) in the core that is larger than R1/(R2+R1) in the outer shell.

3. A method for manufacturing a rare earth magnet, comprising:
a first step of performing hot pressing by using a magnetic powder having a composition of (Nd (1-x) Ce x ) y Fe 100-y-w-z-v Co w B z TM v , wherein TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x≤1 in molar ratio, and y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2 a, in molar percentage; to produce a rare earth magnet precursor, and
a second step of diffusing and impregnating a modifying metal composed of an Nd element or an Nd-TM alloy into the rare earth magnet precursor to manufacture a rare earth magnet comprising a crystal grain having an average grain size of 1,000 nm or less and consisting of a core and an outer shell, and having a composition of Ce/(Nd+Ce) in the core that is larger than Ce/(Nd+Ce) in the outer shell.

4. The method according to claim 1 , wherein the Ce/(Nd+Ce) in the core is 0.25 or more and 1 or less.

5. The method according to claim 2 , wherein the Ce/(Nd+Ce) in the core is 0.25 or more and 1 or less.

6. The method according to claim 3 , wherein the Ce/(Nd+Ce) in the core is 0.25 or more and 1 or less.

7. The method for manufacturing a rare earth magnet according to claim 1 , wherein in the first step, hot press working is performed to produce a compact and the compact is subjected to hot plastic working to produce a rare earth magnet precursor.

8. The method for manufacturing a rare earth magnet according to claim 2 , wherein in the first step, hot press working is performed to produce a compact and the compact is subjected to hot plastic working to produce a rare earth magnet precursor.

9. The method for manufacturing a rare earth magnet according to claim 3 , wherein in the first step, hot press working is performed to produce a compact and the compact is subjected to hot plastic working to produce a rare earth magnet precursor.

10. The method for manufacturing a rare earth magnet according to claim 1 , wherein the average grain size of the crystal grain is 500 nm or less.

11. The method for manufacturing a rare earth magnet according to claim 2 , wherein the average grain size of the crystal grain is 500 nm or less.

12. The method for manufacturing a rare earth magnet according to claim 3 , wherein the average grain size of the crystal grain is 500 nm or less.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ito Masaaki
• Yano Masao
• Kishimoto Hidefumi
• Sakuma Noritsugu
• Shoji Tetsuya
• Manabe Akira

Classifications

• B22F1/17

  Metallic particles coated with metal · CPC title

• C22C33/02 Primary

  by powder metallurgy · CPC title

• B22F1/07

  Metallic powder characterised by particles having a nanoscale microstructure (nanosized particles B22F1/054) · CPC title

• H01F1/0551 Primary

  in the form of particles, e.g. rapid quenched powders or ribbon flakes · CPC title

• B22F2301/45

  Rare earth metals, i.e. Sc, Y, Lanthanides (57-71) · CPC title