# US 2021/0280347 A1 · Insulating material coated soft magnetic powder, powder magnetic core, magnetic element, electronic device, and moving body

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- Number: US 2021/0280347 A1
- Document ID: US20210280347A1
- Status: Published application
- Kind: A1
- Application number: 17/190,461
- Filed: 2021-03-03
- Published: 2021-09-09
- Earliest claimed: 2020-03-05
- Assignees: Seiko Epson Corporation
- Applicants: Seiko Epson Corporation
- Inventors: Atsushi NAKAMURA
- Web page: https://patentgrep.com/patent/US20210280347A1

## CPC

- H01F 1/24: the particles being insulated
- H01F 1/1475: {the particles being insulated}
- H01F 1/14766: {Fe-Si based alloys}
- H01F 1/33: mixtures of metallic and non-metallic particles; metallic particles having oxide skin
- H01F 3/08: made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

An insulating material coated soft magnetic powder, which is a powder body of an insulating material coated soft magnetic particle 1, includes: a core particle 2 including a base portion 2a that includes a soft magnetic material, and an oxide film 2b that is provided on a surface of the base portion 2a and contains an oxide of an element contained in the soft magnetic material, and an insulating film 3b in which a plurality of insulating nanoparticles 3a are attached to the core particle 2. A particle size of each nanoparticle 3a is 1/50,000 or more and 1/100 or less, relative to a particle size of the core particle 2, and after being subjected to a heat treatment in which the core particle 2 is heated at a sintering temperature or higher, a specific resistance after the heat treatment is 110% or more of a specific resistance before the heat treatment.

## Claims

### Claim 1

An insulating material coated soft magnetic powder comprising:
a core particle including a base portion that includes a soft magnetic material, and an oxide film that is provided on a surface of the base portion and contains an oxide of an element contained in the soft magnetic material; and
an insulating film in which a plurality of insulating nanoparticles are attached to the core particle, wherein a particle size of each nanoparticle is 1/50,000 or more and 1/100 or less relative to a particle size of the core particle, and
after being subjected to a heat treatment in which the core particle is heated at a sintering temperature or higher, a specific resistance after the heat treatment is 110% or more of a specific resistance before the heat treatment.

### Claim 2 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
the insulating film is in a state in which a part or all of the plurality of nanoparticles attached to the core particle are melted and integrated with the core particle.

### Claim 3 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
the nanoparticles preferably contain at least one of aluminum oxide, silicon oxide, zirconium oxide, and silicon nitride.

### Claim 4 (depends on 3)

The insulating material coated soft magnetic powder according to claim 3, wherein
the oxide film preferably contains at least one of silicon oxide, aluminum oxide, and chromium oxide.

### Claim 5 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
a thickness of the oxide film is 5 nm or more and 200 nm or less.

### Claim 6 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
a thickness of the insulating film is 3 nm or more and 150 nm or less.

### Claim 7 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
at least a part of the insulating film and the oxide film are melted and integrated.

### Claim 8 (depends on 1)

The insulating material coated soft magnetic powder according to claim 1, wherein
a particle size of the core particle is 1 μm or more and 50 μm or less.

### Claim 9 (depends on 1)

A powder magnetic core comprising:
the insulating material coated soft magnetic powder according to claim 1.

### Claim 10 (depends on 9)

A magnetic element comprising:
the powder magnetic core according to claim 9.

### Claim 11 (depends on 10)

An electronic device comprising:
the magnetic element according to claim 10.

### Claim 12 (depends on 10)

A moving body comprising:
the magnetic element according to claim 10.