Dust core

Patent metadata

Field	Value
Publication number	US-11043320-B2
Application number	US-201815915901-A
Country	US
Kind code	B2
Filing date	Mar 8, 2018
Priority date	Mar 9, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A dust core includes a metal magnetic material, a resin, and an insulation film. The insulation film contacts with a surface of the metal magnetic material and covers the metal magnetic material. The insulation film includes a first film and a second film. The first film contacts with the surface of the metal magnetic material. The second film contacts with a surface of the first film. A density of the first film is higher than a density of the second film.

First claim

The invention claimed is:

1. A dust core comprising:
a metal magnetic particle;
a resin; and
an insulation film contacting with a surface of the metal magnetic particle and covering the metal magnetic particle,
wherein the insulation film comprises:
a first film contacting with the surface of the metal magnetic particle; and
a second film contacting with a surface of the first film,
wherein the first film and the second film are made of a same material, and
wherein a density of the first film is higher than a density of the second film.

2. The dust core according to claim 1 , wherein each of the first film and the second film comprises a Si—O based oxide.

3. The dust core according to claim 2 , wherein the first film and the second film comprise different contrasts from each other observed by TEM.

4. The dust core according to claim 2 , wherein 1.25<I 1 /I 2 <10.0 is satisfied, where I 1 is a Si detection intensity of the first film, and I 2 is a Si detection intensity of the second film, in TEM-EDS analysis of the first film and the second film.

5. The dust core according to claim 3 , wherein 1.25<I 1 /I 2 <10.0 is satisfied, where I 1 is a Si detection intensity of the first film, and I 2 is a Si detection intensity of the second film, in TEM-EDS analysis of the first film and the second film.

6. The dust core according to claim 1 , wherein 0.075<D 1 /D 2 <10.0 is satisfied, where D 1 is a thickness of the first film, and D 2 is a thickness of the second film.

7. The dust core according to claim 2 , wherein 0.075<D 1 /D 2 <10.0 is satisfied, where D 1 is a thickness of the first film, and D 2 is a thickness of the second film.

8. The dust core according to claim 3 , wherein 0.075<D 1 /D 2 <10.0 is satisfied, where D 1 is a thickness of the first film, and D 2 is a thickness of the second film.

9. The dust core according to claim 4 , wherein 0.075<D 1 /D 2 <10.0 is satisfied, where D 1 is a thickness of the first film, and D 2 is a thickness of the second film.

10. The dust core according to claim 5 , wherein 0.075<D 1 /D 2 <10.0 is satisfied, where D 1 is a thickness of the first film, and D 2 is a thickness of the second film.

11. The dust core according to claim 1 , wherein the metal magnetic particle comprises a main component of Fe.

12. The dust core according to claim 2 , wherein the metal magnetic particle comprises a main component of Fe.

13. The dust core according to claim 3 , wherein the metal magnetic particle comprises a main component of Fe.

14. The dust core according to claim 4 , wherein the metal magnetic particle comprises a main component of Fe.

15. The dust core according to claim 6 , wherein the metal magnetic particle comprises a main component of Fe.

16. The dust core according to claim 1 , wherein the metal magnetic particle comprises a main component of Fe and Si.

17. The dust core according to claim 2 , wherein the metal magnetic particle comprises a main component of Fe and Si.

18. The dust core according to claim 3 , wherein the metal magnetic particle comprises a main component of Fe and Si.

19. The dust core according to claim 4 , wherein the metal magnetic particle comprises a main component of Fe and Si.

Assignees

• Tdk Corp

Inventors

• Kamiya Masahiro
• Yamashita Yasuhide
• Sato Chiomi
• FUTAMATA Yousuke
• Nakazawa Ryoma
• Takahashi Takeshi
• Ono Hiroyuki

Classifications

• B22F1/16

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• H01F1/26

  by macromolecular organic substances · CPC title

• H01F41/0246

  Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36) · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• H01F1/14766

  Fe-Si based alloys · CPC title