Metal magnetic particle, inductor, method for manufacturing metal magnetic particle, and method for manufacturing metal magnetic core

Patent metadata

Field	Value
Publication number	US-12191065-B2
Application number	US-202117201801-A
Country	US
Kind code	B2
Filing date	Mar 15, 2021
Priority date	Mar 27, 2020
Publication date	Jan 7, 2025
Grant date	Jan 7, 2025

Abstract

A metal magnetic particle provided with an oxide layer on a surface of an alloy particle containing Fe and Si, wherein the oxide layer has a first oxide layer, a second oxide layer, and a third oxide layer from the alloy particle side. Also, in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer where Si content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, and the third oxide layer is a layer where Si content takes a local maximum value.

First claim

What is claimed is:

1. A metal magnetic core, comprising:
metal magnetic particles, the metal magnetic particles comprising:
an oxide layer formed on a surface of an alloy particle containing Fe and Si, the oxide layer including a first oxide layer, a second oxide layer, and a third oxide layer, the first oxide layer is formed directly on the alloy particle, the second oxide layer formed over the first oxide layer, and the third oxide layer formed over the second oxide layer, and
wherein
in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy,
the first oxide layer is a layer in which Si content takes a local maximum value, and the first oxide layer contains Fe and Si,
the second oxide layer is a layer in which Fe content takes a local maximum value,
the amount of Fe in the second oxide layer is greater than the amount of Si in the second oxide layer,
the third oxide layer is a layer in which Si content takes a local maximum value, and
the metal magnetic particles are joined to each other with the oxide layer to form the metal magnetic core.

2. A metal magnetic core according to claim 1 , wherein
a weight percentage of Si in the alloy particle is from 1.5 parts by weight to 8.0 parts by weight with respect to 100 parts by weight of a total weight of the Fe and the Si.

3. A metal magnetic core according to claim 1 , wherein
the alloy particle contains smaller than 1.0 part by weight of Cr with respect to 100 parts by weight of a total weight of the Fe and the Si.

4. A metal magnetic core according to claim 1 , wherein
the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and
in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy,
the fourth oxide layer is a layer in which Fe content takes a local maximum value.

5. An inductor comprising:
the metal magnetic core according to claim 1 .

6. A metal magnetic core according to claim 2 , wherein
the alloy particle contains smaller than 1.0 part by weight of Cr with respect to 100 parts by weight of a total weight of the Fe and the Si.

7. A metal magnetic core according to claim 2 , wherein
the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and
in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value.

8. A metal magnetic core according to claim 3 , wherein
the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and
in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value.

9. A metal magnetic core according to claim 6 , wherein
the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and
in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value.

10. An inductor comprising:
the metal magnetic core according to claim 2 .

11. An inductor comprising:
the metal magnetic core according to claim 3 .

12. An inductor comprising:
the metal magnetic core according to claim 4 .

13. A metal magnetic core according to claim 1 , wherein a ratio of the Fe content to the Si content (Fe content/Si content) at the point where Fe content of the second oxide layer takes the local maximum value is equal to or larger than about 22 and equal to or smaller than about 27.

14. A metal magnetic core according to claim 1 , wherein
a maximum value of Fe content in the first oxide layer is greater than a maximum value of Fe content in the third oxide layer.

15. A metal magnetic core according to claim 1 , wherein
a minimum value of Fe content in the first oxide layer is greater than a minimum value of Fe content in the third oxide layer.

Assignees

• Murata Manufacturing Co

Inventors

• Ishida Takuya
• Yamamoto Makoto
• Uji Katsutoshi
• Ishida Yuya
• Odahara Mitsuru

Classifications

• H01F1/147

  Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)} · CPC title

• H01F41/0246 Primary

  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

• H01F1/24

  the particles being insulated · CPC title

• H01F1/33 Primary

  mixtures of metallic and non-metallic particles; metallic particles having oxide skin · CPC title

• H01F3/08

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title