Permanent magnet and method for manufacturing the same, and motor and power generator using the same

Patent metadata

Field	Value
Publication number	US-9583243-B2
Application number	US-201113048321-A
Country	US
Kind code	B2
Filing date	Mar 15, 2011
Priority date	Sep 24, 2010
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

In an embodiment, a permanent magnet includes a composition of R (Fe p M q Cu r (Co 1-s A s ) 1-p-q-r ) z (R: rare earth element, M: Ti, Zr, Hf, A: Ni, V, Cr, Mn, Al, Si, Ga, Nb, Ta, W, 0.05≦p 0.6, 0.005≦q≦0.1, 0.01≦r≦0.15, 0≦s≦0.2, 4≦z≦9). The permanent magnet includes a two-phase structure of a Th 2 Zn 17 crystal phase and a copper-rich phase. An average interval between the copper-rich phases in a cross section including a crystal c axis of the Th 2 Zn 17 crystal phase is in a range of over 120 nm and less than 500 nm.

First claim

What is claimed is:

1. A permanent magnet comprising:
a composition expressed by the following composition formula:
Sm(Fe p M q Cu r (Co 1-s A s ) 1-p-q-r ) z ,

wherein M is at least one element selected from the group consisting of Ti, Zr, and Hf, wherein a content of Ti is 10 atomic % or less of the element M,
A is at least one element selected from the group consisting of Ni, V, Cr, Mn, Al, Nb, Ta, and W,
p is a number, which is an atomic ratio, satisfying 0.31≦p≦0.6,
q is a number, which is an atomic ratio, satisfying 0.005≦q≦0.1,
r is a number, which is an atomic ratio, satisfying 0.01≦r≦0.15,
s is a number, which is an atomic ratio, satisfying 0≦s≦0.2,
z is a number, which is an atomic ratio, satisfying 4≦z≦9; and
a structure which comprises a Th 2 Zn 17 crystal phase and a copper-rich phase having a copper concentration by weight percent from 1.2 to 5 times a copper concentration by weight percent in the Th 2 Zn 17 crystal phase,
wherein an average interval d between the copper-rich phases in a cross section including a crystal c axis of the Th 2 Zn 17 crystal phase is greater than 120 nm and less than 500 nm, and
wherein a magnetic coercive force of the permanent magnet is from 100 to 500 kA/m, and a residual magnetization of the permanent magnet is 1.17 T or more.

2. The permanent magnet according to claim 1 ,
wherein an average thickness of the copper-rich phase is in a range from 1 to 20 nm.

3. The permanent magnet according to claim 1 ,
wherein 50 atomic % or more of the element M is zirconium.

4. A variable magnetic flux motor, comprising:
the permanent magnet according to claim 1 as a variable magnet.

5. A variable magnetic flux generator, comprising:
the permanent magnet according to claim 1 as a variable magnet.

6. The permanent magnet according to claim 1 ,
wherein a ratio of H(minor) to H(major) of the permanent magnet is less than 0.95, where H(major) is a magnetic field at the time when magnetization reaches 80% of a saturation magnetization Ms in a major loop, and H(minor) is a magnetic field at the time when magnetization reaches 80% of the saturation magnetization Ms in a minor loop.

7. The permanent magnet according to claim 1 ,
wherein the permanent magnet is a variable magnet.

8. The permanent magnet according to claim 1 ,
wherein 50 atomic % or more and 90 atomic % or less of the element M is zirconium.

9. The permanent magnet according to claim 1 ,
wherein the structure of the permanent magnet consists essentially of the Th 2 Zn 17 crystal phase and the copper-rich phase.

10. The permanent magnet according to claim 1 ,
wherein the element M is zirconium.

11. The permanent magnet according to claim 1 ,
wherein the composition is expressed by the following composition formula:
Sm(Fe p M q Cu r Co 1-p-q-r ) z ,

wherein M is at least one element selected from the group consisting of Ti, Zr, and Hf, wherein a content of Ti is 10 atomic % or less of the element M,
p is a number, which is an atomic ratio, satisfying 0.31≦p≦0.6,
q is a number, which is an atomic ratio, satisfying 0.005≦q≦0.1,
r is a number, which is an atomic ratio, satisfying 0.01≦r≦0.15,
sz is a number, which is an atomic ratio, satisfying 4≦z≦9.

12. A method for manufacturing a permanent magnet, comprising:
fabricating an alloy powder having a composition expressed by the following composition formula:
Sm(Fe p M q Cu r (Co 1-s A s ) 1-p-q-r ) z ,

wherein M is at least one element selected from the group consisting of Ti, Zr, and Hf, wherein a content of Ti is 10 atomic % or less of the element M,
A is at least one element selected from the group consisting of Ni, V, Cr, Mn, Al, Nb, Ta, and W,
p is a number, which is an atomic ratio, satisfying 0.31≦p≦0.6,
q is a number, which is an atomic ratio, satisfying 0.005≦q≦0.1,
r is a number, which is an atomic ratio, satisfying 0.01≦r≦0.15,
s is a number, which is an atomic ratio, satisfying 0≦s≦0.2,
z is a number, which is an atomic ratio, satisfying 4≦z≦9; and
press-forming the alloy powder in a magnetic field to form a pressed powder body;
sintering the pressed powder body to form a sintered body;
performing a solution treatment to the sintered body;
performing an aging treatment to the sintered body after the solution treatment at a temperature T ° C. satisfying 805° C.≦T or TB+50<T<TB+150 for from 0.25 to 8 hours, wherein TB ° C. is a temperature represented by the formula: 3500p−5000q−(50p) 2 , and
fabricating a sintered magnet as the permanent magnet by cooling the sintered body after the aging treatment at a cooling speed of from 1.3 to 2° C./min,
wherein the sintered magnet comprises a structure which includes a Th 2 Zn 17 crystal phase and a copper-rich phase having a copper concentration by weight percent in a range from 1.2 to 5 times a copper concentration by weight percent in the Th 2 Zn 17 crystal phase,
wherein an average interval d between the copper-rich phases in a cross section including a crystal c axis of the Th 2 Zn 17 crystal phase is in a range of over 120 nm and less than 500 nm, and
wherein the sintered magnet has a magnetic coercive force of from 100 to 500 kA/m and a residual magnetization of 1.17 T or more.

13. The manufacturing method according to claim 12 ,
wherein an average thickness of the copper-rich phase in the sintered magnet is from 1 to 20 nm.

14. The manufacturing method according to claim 12 ,
wherein the sintered magnet has a ratio of H(minor) to H(major) of less than 0.95, where H(major) is a magnetic field at the time when magnetization reaches 80% of a saturation magnetization Ms in a major loop, and H(minor) is a magnetic field at the time when magnetization reaches 80% of the saturation magnetization Ms in a minor loop.

15. The manufacturing method according to claim 12 ,
wherein the solution treatment is performed at a temperature of from 1130 to 1230° C. for from 0.5 to 8 hours.

16. The manufacturing method according to claim 12 ,
wherein 50 atomic % or more and 90 atomic % or less of the element M is zirconium.

17. The manufacturing method according to claim 12 ,
wherein the structure of the sintered magnet consists essentially of the Th 2 Zn 17 crystal phase and the copper-rich phase.

18. The manufacturing method according to claim 12 ,
wherein the element M is zirconium.

19. The manufacturing method according to claim 12 ,
wherein the composition is expressed by the following composition formula:
Sm(Fe p M q Cu r Co 1-p-q-r ) z ,

wherein M is at least one element selected from the group consisting of Ti, Zr, and Hf, wherein a content of Ti is 10 atomic % or less of the element M,
p is a number, which is an atomic ratio, satisfying 0.31≦p≦0.6,
q is a number, which is an atomic ratio, satisfying 0.005≦q≦0.1,
r is a number, which is an atomic ratio, satisfying 0.01≦r≦0.15,
sz is a number, which is an atomic ratio, satisfying 4≦z≦9.

Assignees

• Horiuchi Yosuke
• Sakurada Shinya
• Okamoto Keiko
• Hagiwara Masaya
• Toshiba Kk

Inventors

• Horiuchi Yosuke
• Sakurada Shinya
• Okamoto Keiko
• Hagiwara Masaya

Classifications

• C22C38/10

  containing cobalt · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title

• C21D8/1205

  involving particular fabrication steps or treatments of ingots or slabs · CPC title

• C22C38/14

  containing titanium or zirconium · CPC title

• C22C2202/02

  Magnetic · CPC title