Magnetic compound and production method thereof

Patent metadata

Field	Value
Publication number	US-10937577-B2
Application number	US-201615233362-A
Country	US
Kind code	B2
Filing date	Aug 10, 2016
Priority date	Sep 17, 2015
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A magnetic compound represented by the formula (R1(1-x)R2x)a(Fe(1-y)Coy)bTcMd wherein R1 is one or more elements selected from the group consisting of Sm, Pm, Er, Tm and Yb, R2 is one or more elements selected from the group consisting of Zr, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho and Lu, T is one or more elements selected from the group consisting of Ti, V, Mo, Si and W, M is one or more elements selected from the group consisting of unavoidable impurity elements, Al, Cr, Cu, Ga, Ag and Au, 0≤x≤0.7, 0≤y≤0.7, 4≤a≤20, b=100-a-c-d, 0<c<7.7, and 0≤d≤3, the magnetic compound having a ThMn12-type crystal structure, wherein the volume fraction of α-(Fe, Co) phase is less than 12.3%.

First claim

What is claimed is:

1. A magnetic compound, its composition being represented by the formula in atomic percentage:
(R 1 (1-x) R 2 x ) a (Fe (1-y) Co y ) b T c M d
wherein
R 1 is Sm,
R 2 is Zr,
T is Ti,
M is one or more unavoidable impurity elements,
0≤x≤0.7,
0≤y≤0.7,
4≤a≤20,
b=100-a-c-d,
0<c<7.7, and
0≤d≤2, and
wherein the magnetic compound has a ThMn 12 -type crystal structure and an α-(Fe, Co) phase of less than 12.3% in volume fraction,
wherein when hexagons A, B and C are defined as:
A: a six-membered ring centering on a rare earth atom R 1 and consisting of Fe (8i) and Fe(8j) sites,
B: a six-membered ring centering on an Fe (8i)-Fe (8i) dumbbell and consisting of Fe (8i) and Fe(8j) sites, and
C: a six-membered ring centering on an Fe (8i)-rare earth atom line and consisting of Fe(8j) and Fe(8f) sites,
the ThMn 12 --type crystal structure has these hexagons A, B and C and the length in the axis a direction of hexagon A is 0.607 nm or more and 0.612 nm or less.

2. The magnetic compound according to claim 1 , wherein 0≤x≤0.4.

3. The magnetic compound according to claim 1 , wherein 4≤a≤15.

4. The magnetic compound according to claim 1 , wherein 3.8≤c<7.7.

5. The magnetic compound according to claim 1 , wherein 0≤y≤0.4.

6. The magnetic compound according to claim 1 , wherein the volume fraction of α-(Fe, Co) phase is 10% or less.

7. A method for producing the magnetic compound according to claim 1 , comprising:
a step of preparing a molten alloy, its composition being represented by the formula in atomic percentage:
(R 1 (1-x) R 2 x ) a (Fe (1-y) Co y ) b T c M d

wherein
R 1 is Sm,
R 2 is Zr,
T is Ti,
0≤x≤0.7,
0≤y≤0.7,
4≤a≤20
b=100-a-c-d,
0<c<7.7, and
0≤d≤2,

and
a step of quenching the molten alloy at a rate of 1×10 2 to 1×10 7 K/sec.

8. The method according to claim 7 , further comprising a step of performing a heat treatment at 800 to 1,300° C. for 2 to 120 hours after the quenching step.

9. The method according to claim 7 , wherein 0≤x≤0.4.

10. The method according to claim 7 , wherein 4≤a≤15.

11. The method according to claim 7 , wherein 3.8≤c<7.7.

12. The method according to claim 7 , wherein 0≤y≤0.4.

Assignees

• Toyota Motor Co Ltd

Inventors

• Sakuma Noritsugu
• Yano Masao
• Kato Akira
• Manabe Akira
• Suzuki Shunji
• Kobayashi Kurima

Classifications

• H01F41/0253

  for manufacturing permanent magnets · CPC title

• H01F1/0557 Primary

  sintered · CPC title

• C22C38/14

  containing titanium or zirconium · CPC title

• H01F1/055 Primary

  and magnetic transition metals, e.g. SmCo5 · CPC title

• C22C38/10

  containing cobalt · CPC title