# US 10,480,052 B2 · Permanent magnet, and motor and generator using the same

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- Number: US 10,480,052 B2
- Document ID: US10480052B2
- Status: Granted
- Kind: B2
- Application number: 15/253,945
- Filed: 2016-09-01
- Published: 2017-01-05
- Granted: 2019-11-19
- Earliest claimed: 2014-03-19
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Applicants: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Inventors: Masaya Hagiwara; Shinya Sakurada; Yosuke Horiuchi; Tadahiko Kobayashi; Tsuyoshi Kobayashi; Masaki Endo; Naoyuki Sanada; Masami Okamura; Takao Sawa; Keiichi Fuse; Satoru Habu
- Web page: https://patentgrep.com/patent/US10480052B2

## CPC

- C22C 30/02: containing copper
- B22F 5/00: Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
- C22C 19/07: based on cobalt
- C22C 21/06: with magnesium as the next major constituent
- H01F 1/0536: {sintered}
- H01F 1/0557: {sintered}
- H01F 1/086: {sintered}
- H02K 1/02: characterised by the magnetic material
- C22C 2202/02: Magnetic
- H01F 1/0596: {of rhombic or rhombohedral Th2Zn17 structure or hexagonal Th2Ni17 structure}
- H01F 7/0226: {PM with variable field strength (H01F7/0284 takes precedence)}
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A permanent magnet of the embodiment includes: a composition represented by a composition formula: R(FepMqCurCtCo1-p-q-r-t)z (R is at least one element selected from rare-earth elements, M is at least one element selected from Ti, Zr and Hf, 0.27≤p≤0.45, 0.01≤q≤0.05, 0.01≤r≤0.1, 0.002≤t≤0.03, and 6≤z≤9); and a metallic structure including a main phase containing a Th2Zn17 crystal phase, and a sub phase of the element M having an element M concentration of 30 atomic % or more. The sub phase of the element M precipitates in the metallic structure. A ratio of a circumferential length to a precipitated area of the sub phase of the element M is 1 or more and 10 or less.

## Claims

### Claim 1

A permanent magnet comprising:
a composition represented by a composition formula:
R(FepMqCurCtCo1-p-q-r-t)z
wherein 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 Ti, Zr and Hf, p is a number, which is an atomic ratio, satisfying 0.27≤p≤0.45, q is a number, which is an atomic ratio, satisfying 0.01≤q≤0.05, r is a number, which is an atomic ratio, satisfying 0.01≤r≤0.1, t is a number, which is an atomic ratio, satisfying 0.002≤t≤0.03, and z is a number, which is an atomic ratio, satisfying 6≤r≤9; and
a metallic structure including a main phase containing a Th2Zn17 crystal phase, and a sub phase of the element M having an element M concentration of 30 atomic % or more and containing carbide of element M,
wherein the sub phase precipitates in the metallic structure, and a ratio of a circumferential length to a precipitated area of the sub phase is 2 or more and 9.2 or less, and a number of precipitates per a unit area, which is 50 mm×50 mm, of the sub phase is two or more.

### Claim 2 (depends on 1)

The permanent magnet according to claim 1, comprising a sintered compact including the composition and the metallic structure,
wherein the sub phase precipitates in at least one of crystal grains or a crystal grain boundary forming the sintered compact.

### Claim 3 (depends on 2)

The permanent magnet according to claim 2,
wherein the sintered compact is obtained by heating-up a green compact of magnetic ally powder to a sintering temperature of 1100° C. or more and 1300° C. or more at a rate of 10° C./min or more and 25° C./min or less, and sintering at the sintering temperature.

### Claim 4 (depends on 1)

The permanent magnet according to claim 1,
wherein the main phase includes a cell phase having the Th2Zn17 crystal phase, a cell wall phase existing to surround the cell phase, and a platelet phase.

### Claim 5 (depends on 1)

The permanent magnet according to claim 1,
wherein 50 atomic % or more of the element M in the composition formula is Zr.

### Claim 6 (depends on 1)

The permanent magnet according to claim 1,
wherein 50 atomic % or more of the element R in the composition formula is Sm.

### Claim 7 (depends on 1)

A motor comprising the permanent magnet according to claim 1.

### Claim 8 (depends on 7)

A vehicle comprising the motor according to claim 7.

### Claim 9 (depends on 1)

A generator comprising the permanent magnet according to claim 1.

### Claim 10 (depends on 9)

A vehicle comprising the generator according to claim 9.

### Claim 11 (depends on 1)

The permanent magnet according to claim 1,
wherein the ratio of the circumferential length to the precipitated area of the sub phase is 4.1 or more and 9.2 or less.

### Claim 12 (depends on 1)

The permanent magnet according to claim 1,
wherein a number of precipitates per a unit area, which is 50 mm×50 mm, of the sub phase is 2 or more and 40 or less.

### Claim 13

A permanent magnet comprising:
a composition represented by a composition formula:
R(FepMqCurCt(Co100-aAa)1-p-q-r-t)z
wherein 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 Ti, Zr and Hf, A is at least one element selected from the group consisting of Ni, V, Cr, Mn, Al, Si, Ga, Nb, Ta, and W, p is a number, which is an atomic ratio, satisfying 0.27≤p≤0.45, q is a number, which is an atomic ratio, satisfying 0.01≤q≤0.05, r is a number, which is an atomic ratio, satisfying 0.01≤r≤0.1, t is a number, which is an atomic ratio, satisfying 0.002≤t≤0.03, z is a number, which is an atomic ratio, satisfying 6≤r≤9, and a is 20 atomic % or less; and
a metallic structure including a main phase containing a Th2Zn17 crystal phase, and a sub phase of the element M having an element M concentration of 30 atomic % or more and containing carbide of element M,
wherein the sub phase precipitates in the metallic structure, and a ratio of a circumferential length to a precipitated area of the sub phase is 2 or more and 9.2 or less, and a number of precipitates per a unit area, which is 50 mm×50 mm, of the sub phase is two or more.