Permanent magnet, motor, and generator

Patent metadata

Field	Value
Publication number	US-10650947-B2
Application number	US-201514636268-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Mar 19, 2014
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

The invention provides a high-performance permanent magnet. The permanent magnet has a composition that is expressed by a composition formula R p Fe q M r Cu t Co 100-p-q-r-t , where R is at least one element selected from a rare earth element, M is at least one element selected from the group consisting of Zr, Ti, and Hf, p is a number satisfying 10.8≤p≤12.5 atomic percent, q is a number satisfying 25≤q≤40 atomic percent, r is a number satisfying 0.88≤r≤4.5 atomic percent, and t is a number satisfying 3.5≤t≤13.5 atomic percent. The permanent magnet also has a metallic structure that includes a main phase having a Th 2 Zn 17 crystal phase, and a Cu-M rich phase having a higher Cu concentration and a higher M concentration than the main phase.

First claim

What is claimed is:

1. A permanent magnet comprising:
a composition expressed by a composition formula R p Fe q M r Cu t Co 100-p-q-r-t , where R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Zr, Ti, and Hf, p is a number satisfying 10.8≤p≤12.5 atomic percent, q is a number satisfying 26≤q≤40 atomic percent, r is a number satisfying 0.88≤r≤4.5 atomic percent, and t is a number satisfying 4.91≤t≤13.5 atomic percent; and
a metallic structure including a main phase having a Th 2 Zn 17 crystal phase, and Cu-M rich phases, each of the Cu-M rich phases having a higher Cu concentration and a higher M concentration than the main phase,
an average value of diameters of the Cu-M rich phases being equal to or smaller than 10 μm,
a squareness ratio of the magnet being 93.5% or more and 95.5% or less, and
a residual magnetization of the magnet being 1.17 T or more and 1.215 T or less.

2. The permanent magnet of claim 1 ,
wherein the metallic structure includes a grain boundary phase disposed between crystal grains of the main phase, and the grain boundary phase has one of the Cu-M rich phases.

3. The permanent magnet of claim 1 ,
wherein an average grain diameter of crystal grains of the main phase is equal to or greater than 35 μm.

4. The permanent magnet of claim 1 ,
wherein the Cu-M rich phase has a composition expressed by a composition formula R p1 Fe q1 M r1 Cu t1 Co 100-p1-q1-r1-t1 , where p1 is a number satisfying 8≤p1≤20 atomic percent, q1 is a number satisfying 15≤q1≤35 atomic percent, r1 is a number satisfying 2<r1≤15 atomic percent, and t1 is a number satisfying 5≤t1≤25 atomic percent.

5. The permanent magnet of claim 1 ,
wherein the main phase has a cell phase having the Th 2 Zn 17 crystal phase, and a Cu rich phase having a higher Cu concentration than the cell phase.

6. The permanent magnet of claim 1 , wherein 50 atomic percent or more of a total amount of the R element in the composition formula is Sm, and 50 atomic percent or more of the M element in the composition formula is Zr.

7. A motor comprising the permanent magnet recited in claim 1 .

8. A vehicle comprising the motor recited in claim 7 .

9. A generator comprising the permanent magnet recited in claim 1 .

10. A vehicle comprising the generator recited in claim 9 .

11. The permanent magnet of claim 1 ,
wherein the squareness ratio is 94.0% or more and 95.5% or less.

12. A permanent magnet comprising:
a composition expressed by a composition formula R p Fe q M r Cu t Co 100-p-q-r-t , where R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Zr, Ti, and Hf, p is a number satisfying 10.8≤p≤12.5 atomic percent, q is a number satisfying 26≤q≤40 atomic percent, r is a number satisfying 0.88≤r≤4.5 atomic percent, and t is a number satisfying 4.91≤t≤13.5 atomic percent; and
a metallic structure including a main phase having a Th 2 Zn 17 crystal phase, and a grain boundary phase disposed between crystal grains of the main phase, the grain boundary phase having a Cu-M rich phase, the Cu-M rich phase having a higher Cu concentration and a higher M concentration than the main phase,
the crystal grains of the main phase having an average grain diameter being equal to or greater than 35 μm,
a squareness ratio of the magnet being 93.5% or more and 95.5% or less, and
a residual magnetization of the magnet being 1.17 T or more and 1.215 T or less.

13. The permanent magnet according to claim 12 , wherein the Cu-M rich phase has a composition expressed by a composition formula R p1 Fe q1 M r1 Cu t1 Co 100-p1-q1-r1-t1 , where p1 is a number satisfying 8≤p1≤20 atomic percent, q1 is a number satisfying 15≤q1≤35 atomic percent, r1 is a number satisfying 2<r1≤15 atomic percent, and t1 is a number satisfying 5≤t1≤25 atomic percent.

14. The permanent magnet of claim 12 , wherein the main phase has a cell phase having the Th 2 Zn 17 crystal phase, and a Cu rich phase having a higher Cu concentration than the cell phase.

15. The permanent magnet of claim 12 , wherein 50 atomic percent or more of a total amount of the R element in the composition formula is Sm, and 50 atomic percent or more of the M element in the composition formula is Zr.

16. A motor comprising the permanent magnet recited in claim 12 .

17. A vehicle comprising the motor recited in claim 16 .

18. A generator comprising the permanent magnet recited in claim 12 .

19. A vehicle comprising the generator recited in claim 18 .

20. The permanent magnet of claim 12 ,
wherein the squareness ratio is 94.0% or more and 95.5% or less.

Assignees

• Toshiba Kk

Inventors

• Horiuchi Yosuke
• Sakurada Shinya
• Okamoto Keiko
• Hagiwara Masaya
• Kobayashi Tsuyoshi
• Endo Masaki
• Kobayashi Tadahiko
• Sanada Naoyuki

Classifications

• B22F2009/044

  by jet milling · CPC title

• H01F1/0557

  sintered · CPC title

• H01F1/0536

  sintered · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• H02K1/02

  characterised by the magnetic material · CPC title