# US 10,872,717 B2 · Composite magnetic material and magnetic core

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- Number: US 10,872,717 B2
- Document ID: US10872717B2
- Status: Granted
- Kind: B2
- Application number: 16/007,485
- Filed: 2018-06-13
- Published: 2019-01-03
- Granted: 2020-12-22
- Earliest claimed: 2017-06-30
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Yu Yonezawa; Yoshihiro Shinkai
- Web page: https://patentgrep.com/patent/US10872717B2

## CPC

- H01F 1/28: dispersed or suspended in a bonding agent
- B22F 1/054: Nanosized particles
- B22F 1/0547: {Nanofibres or nanotubes}
- B22F 1/065: Spherical particles
- B22F 1/07: Metallic powder characterised by particles having a nanoscale microstructure (nanosized particles B22F1/054)
- B22F 1/10: Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
- C22C 38/10: containing cobalt
- H01F 3/08: made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06)
- B22F 2301/35: Iron
- B22F 2304/054: Particle size between 1 and 100 nm
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- C22C 2202/02: Magnetic
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- 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
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A composite magnetic material includes a needle-like powder and a spherical powder. The needle-like powder includes a soft magnetic material and has an average minor-axis length of 100 nm or less and an average aspect ratio of 3.0 or more and 10.0 or less. The spherical powder includes a soft magnetic material and has an average major-axis length of 100 nm or less and an average aspect ratio of less than 3.0.

## Claims

### Claim 1

A composite magnetic material, comprising a needle-like powder and a spherical powder, wherein
the needle-like powder comprises a soft magnetic material and has an average minor-axis length of 100 nm or less and an average aspect ratio of 3.0 or more and 10.0 or less, and
the spherical powder comprises a soft magnetic material and has an average major-axis length of 100 nm or less and an average aspect ratio of less than 3.0.

### Claim 2 (depends on 1)

The composite magnetic material according to claim 1, further comprising a resin.

### Claim 3 (depends on 1)

The composite magnetic material according to claim 1, wherein the soft magnetic materials of the needle-like powder and the spherical powder comprise a main component of Fe or Fe and Co.

### Claim 4 (depends on 2)

The composite magnetic material according to claim 2, wherein the soft magnetic materials of the needle-like powder and the spherical powder comprise a main component of Fe or Fe and Co.

### Claim 5 (depends on 3)

The composite magnetic material according to claim 3, wherein a content ratio of Co to the main component is 0 to 40 atom % (excluding 0 atom %) in the needle-like powder.

### Claim 6 (depends on 4)

The composite magnetic material according to claim 4, wherein a content ratio of Co to the main component is 0 to 40 atom % (excluding 0 atom %) in the needle-like powder.

### Claim 7 (depends on 1)

The composite magnetic material according to claim 1, wherein a content ratio of the needle-like powder is 60 vol % or more and 90 vol % or less with respect to a total of the needle-like powder and the spherical powder.

### Claim 8 (depends on 2)

The composite magnetic material according to claim 2, wherein a content ratio of the needle-like powder is 60 vol % or more and 90 vol % or less with respect to a total of the needle-like powder and the spherical powder.

### Claim 9 (depends on 3)

The composite magnetic material according to claim 3, wherein a content ratio of the needle-like powder is 60 vol % or more and 90 vol % or less with respect to a total of the needle-like powder and the spherical powder.

### Claim 10 (depends on 5)

The composite magnetic material according to claim 5, wherein a content ratio of the needle-like powder is 60 volt % or more and 90 vol. % or less with respect to a total of the needle-like powder and the spherical powder.

### Claim 11 (depends on 1)

The composite magnetic material according to claim 1, wherein the spherical powder has an average aspect ratio of 1.5 or more and 2.5 or less.

### Claim 12 (depends on 2)

The composite magnetic material according to claim 2, wherein the spherical powder has an average aspect ratio of 1.5 or more and 2.5 or less.

### Claim 13 (depends on 3)

The composite magnetic material according to claim 3, wherein the spherical powder has an average aspect ratio of 1.5 or more and 2.5 or less.

### Claim 14 (depends on 5)

The composite magnetic material according to claim 5, wherein the spherical powder has an average aspect ratio of 1.5 or more and 2.5 or less.

### Claim 15 (depends on 7)

The composite magnetic material according to claim 7, wherein the spherical powder has an average aspect ratio of 1.5 or more and 2.5 or less.

### Claim 16 (depends on 1)

A magnetic core comprising the composite magnetic material according to claim 1.

### Claim 17 (depends on 2)

A magnetic core comprising the composite magnetic material according to claim 2.

### Claim 18 (depends on 16)

The magnetic core according to claim 16, wherein a total content ratio of the needle-like powder and the spherical powder is 35 vol % or more with respect to the entire magnetic core.

### Claim 19 (depends on 17)

The magnetic core according to claim 17, wherein a total content ratio of the needle-like powder and the spherical powder is 35 vol % or more with respect to the entire magnetic core.