# US 12,015,306 B2 · Plurality of flaky magnetic metal particles, pressed powder material, and rotating electric machine

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- Number: US 12,015,306 B2
- Document ID: US12015306B2
- Status: Granted
- Kind: B2
- Application number: 16/536,595
- Filed: 2019-08-09
- Published: 2020-09-24
- Granted: 2024-06-18
- Earliest claimed: 2019-03-19
- Assignees: Kabushiki Kaisha Toshiba
- Applicants: Kabushiki Kaisha Toshiba
- Inventors: Tomohiro Suetsuna; Hiroaki Kinouchi; Naoyuki Sanada; Takahiro Kawamoto
- Web page: https://patentgrep.com/patent/US12015306B2

## CPC

- H02K 1/02: characterised by the magnetic material
- B22F 1/068: Flake-like particles
- B22F 1/08: Metallic powder characterised by particles having an amorphous microstructure
- B22F 1/10: Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
- B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10)
- B22F 3/02: Compacting only
- B22F 3/11: Making porous workpieces or articles
- B22F 3/24: After-treatment of workpieces or articles {(B22F3/1146 takes precedence)}
- H01F 1/26: by macromolecular organic substances
- B22F 2003/248: {Thermal after-treatment}
- B22F 2202/05: Use of magnetic field
- B22F 2301/15: Nickel or cobalt
- B22F 2301/35: Iron
- B22F 2302/45: Others, including non-metals
- B22F 2303/01: Main component
- B22F 2998/10: Processes characterised by the sequence of their steps
- C22C 2202/02: Magnetic
- H01F 1/15375: {using polymers}
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- 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
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A plurality of flaky magnetic metal particles have an average thickness of 10 nm to 100 μm, each of the particles having a flat surface; a magnetic metal phase containing at least one element selected from the group consisting of Fe, Co, and Ni; and a difference in coercivity on the basis of direction within the surface, the average value of the ratio of the average length within the surface with respect to the thickness being from 5-10,000. The particles include a particle having at least one of a crack in a thickness direction having a depth equivalent to 10% or more of the thickness of the particle and a width shorter than the depth, and a crack in a direction parallel to the surface having a length equivalent to 10% or more of the thickness of the particle and a width shorter than the length.

## Claims

### Claim 1

A plurality of flaky magnetic metal particles having an average thickness of from 10 nm to 100 μm,
each of the plurality of flaky magnetic metal particles comprising: a flat surface; a magnetic metal phase containing at least one first element selected from the group consisting of iron (Fe), cobalt (Co), and nickel (Ni); and a difference in coercivity on a basis of direction within the flat surface,
the average value of a ratio of an average length within the flat surface with respect to the thickness being from 5 to 10,000, and
multiple ones of the plurality of flaky magnetic metal particles having either a crack in the direction of the thickness of the flaky magnetic metal particle, the crack having a depth equivalent to 10% or more of the thickness of the flaky magnetic metal particle and a width shorter than the depth, or a crack in a direction parallel to the flat surface, the crack having a length equivalent to 10% or more of the thickness of the flaky magnetic metal particle and a width shorter than the length, or the multiple ones of the flaky magnetic metal particles having both of the cracks,
wherein the multiple ones of the plurality of flaky magnetic metal particles having cracks are included at a number proportion of 1% or more.

### Claim 2 (depends on 1)

The plurality of flaky magnetic metal particles according to claim 1, wherein in the multiple ones of the plurality of flaky magnetic metal particles having cracks, a proportion of the difference in coercivity on the basis of direction within the flat surface is 1% or more.

### Claim 3 (depends on 1)

The plurality of flaky magnetic metal particles according to claim 1, wherein in the multiple ones of the plurality of flaky magnetic metal particles having cracks, the flat surface has either or both of a plurality of concavities and a plurality of convexities, the concavities and the convexities being arranged in a first direction within the flat surface, and each of the concavities and the convexities having a width of 0.1 μm or more, a length of 1 μm or more, and an aspect ratio of 2 or higher.

### Claim 4 (depends on 1)

The plurality of flaky magnetic metal particles according to claim 1, wherein in the multiple ones of the plurality of flaky magnetic metal particles having cracks, at least a portion of the surface of the multiple ones of the flaky magnetic metal particles is covered with a coating layer having a thickness of from 0.1 nm to 1 μm and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F).

### Claim 5

A pressed powder material, comprising a plurality of flaky magnetic metal particles and an intercalated phase,
the plurality of flaky magnetic metal particles having an average thickness of from 10 nm to 100 μm,
each of the plurality of flaky magnetic metal particles having a flat surface and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni,
the average value of a ratio of an average length within the flat surface with respect to the thickness being from 5 to 10,000,
multiple ones of the plurality of flaky magnetic metal particles having either a crack in the direction of the thickness of the flaky magnetic metal particle, the crack having a depth equivalent to 10% or more of the thickness of the flaky magnetic metal particle and a width shorter than the depth, or a crack in a direction parallel to the flat surface, the crack having a length equivalent to 10% or more of the thickness of the flaky magnetic metal particle and a width shorter than the length, or the multiple ones of the flaky magnetic metal particle having both of the cracks,
the intercalated phase being present between the plurality of flaky magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F),
the flat surface being oriented in the pressed powder material to be parallel to a plane of the pressed powder material and having a difference in coercivity on a basis of direction within the plane,
wherein in a predetermined cross-section perpendicular to a plane of the pressed powder material, the multiple ones of the plurality of flaky magnetic metal particles having cracks are included at a number proportion of 1% or more with respect to all of the plurality of flaky magnetic metal particles present in the predetermined cross-section perpendicular to the plane of the pressed powder material.

### Claim 6 (depends on 5)

The pressed powder material according to claim 5, wherein the intercalated phase is disposed inside the cracks.

### Claim 7 (depends on 5)

The pressed powder material according to claim 5, wherein the proportion of the difference in coercivity on the basis of direction is 1% or more within the plane of the pressed powder material.

### Claim 8 (depends on 5)

The pressed powder material according to claim 5, wherein the flat surface in the multiple ones of the plurality of flaky magnetic metal particles having cracks includes either or both of a plurality of concavities and a plurality of convexities, the concavities and the convexities being arranged in a first direction within the flat surface, and each of the concavities and the convexities having a width of 0.1 μm or more, a length of 1 μm or more, and an aspect ratio of 2 or higher.

### Claim 9 (depends on 5)

The pressed powder material according to claim 5, wherein the intercalated phase contains an oxide containing at least one third element selected from the group consisting of B, Si, Cr, Mo, Nb, Li, Ba, Zn, La, P, Al, Ge, W, Na, Ti, As, V, Ca, Bi, Pb, Te, and Sn.

### Claim 10 (depends on 5)

The pressed powder material according to claim 5, wherein the intercalated phase contains a resin.

### Claim 11 (depends on 5)

The pressed powder material according to claim 5, wherein a weight reduction percentage of the pressed powder material after heating for 3,000 hours at 180° C. is 5% or less.

### Claim 12 (depends on 5)

The pressed powder material according to claim 5, wherein the pressed powder material includes voids at a proportion of from 1% to 60% as an area ratio in a predetermined cross-section perpendicular to the plane of the pressed powder material.

### Claim 13 (depends on 12)

The pressed powder material according to claim 12, wherein the voids include first void portions present along the flat surfaces of the flaky magnetic metal particles in the predetermined cross-section perpendicular to the plane of the pressed powder material, and include a first void portion having a ratio of the major axis to the minor axis of 2 or higher.

### Claim 14 (depends on 12)

The pressed powder material according to claim 12, wherein the voids include a void being in contact with at least a portion of the flaky magnetic metal particles in the predetermined cross-section perpendicular to the plane of the pressed powder material.

### Claim 15 (depends on 12)

The pressed powder material according to claim 12, wherein the voids include a void being covered with the intercalated phase in the predetermined cross-section perpendicular to the plane of the pressed powder material.

### Claim 16 (depends on 12)

The pressed powder material according to claim 12, wherein the voids include ellipsoid second void portions in the predetermined cross-section perpendicular to the plane of the pressed powder material, and include a second void portion having a ratio of the major axis to the minor axis of from 1 to 10.

### Claim 17 (depends on 16)

The pressed powder material according to claim 16, wherein the second void portions including a second void portion having a minor axis with a length less than or equal to the thickness of the flaky magnetic metal particles present at the closest positions in the direction of the flat surface, in the predetermined cross-section perpendicular to the plane of the pressed powder material.

### Claim 18 (depends on 5)

A rotating electric machine, comprising the pressed powder material according to claim 5.