Soft magnetic powder, method for producing same, and dust core using soft magnetic powder

Patent metadata

Field	Value
Publication number	US-11270821-B2
Application number	US-201816019458-A
Country	US
Kind code	B2
Filing date	Jun 26, 2018
Priority date	Jul 5, 2017
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A soft magnetic powder that can exhibit desirable soft magnetic characteristics. A dust core using the soft magnetic powder is also provided. The soft magnetic powder includes: a soft magnetic powder layer of an unoxidized soft magnetic material; a second oxide layer as an oxide with iron or boron residing around the soft magnetic powder layer; and a first oxide layer of an iron oxide residing around the second oxide layer. The first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface.

First claim

What is claimed is:

1. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
a second oxide layer as an oxide with iron or boron contacting with the soft magnetic powder layer; and
a first oxide layer of an iron oxide contacting with the second oxide layer, wherein:
the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface, and
the first oxide layer is a layer of iron oxide and does not contain Al and Cr.

2. The soft magnetic powder according to claim 1 , wherein the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 100 nm or less from the surface, and are absent in a region of more than 100 nm and 1,600 nm or less from the surface.

3. The soft magnetic powder according to claim 1 , wherein the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 50 nm or less from the surface, and are absent in a region of more than 50 nm and 1,600 nm or less from the surface.

4. A dust core comprising the soft magnetic powder of claim 1 , and a binder.

5. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
a second oxide layer as an oxide with iron or boron residing around the soft magnetic powder layer; and
a first oxide layer of an iron oxide residing around the second oxide layer, wherein:
the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface,
the first oxide layer has a spiked pulverization mark on a powder surface layer, and
an angle formed by the spiked pulverization mark with respect to the powder surface is 30 to 60 degrees.

6. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
an oxide layer of an iron oxide residing around the soft magnetic powder layer; and
a silicon containing layer covering a surface layer of the oxide layer without a break,
the soft magnetic powder having a silicon concentration that continuously increases from a central portion of the soft magnetic powder layer toward a surface layer of the soft magnetic powder layer, and the oxide layer being configured from a first oxide layer residing on the surface-layer side, and a second oxide layer of an oxide with iron or boron residing on the soft-magnetic-powder-layer side.

7. The soft magnetic powder according to claim 6 , wherein the oxide layer has a thickness of 20 nm to 500 nm.

8. The soft magnetic powder according to claim 6 , wherein the silicon containing layer has a thickness of 200 nm to 1 μm.

9. The soft magnetic powder according to claim 6 , wherein the oxide layer has a thickness of 20 nm to 500 nm.

10. A dust core comprising the soft magnetic powder of claim 6 and a binder.

11. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
an oxide layer of an iron oxide residing around the soft magnetic powder layer; and
a silicon containing layer covering a surface layer of the oxide layer without a break, wherein:
the soft magnetic powder has a silicon concentration that continuously increases from a central portion of the soft magnetic powder layer toward a surface layer of the soft magnetic powder layer, and
the silicon containing layer has a silicon concentration that is 0.5 atomic % to 3 atomic % higher than the silicon concentration of the soft magnetic powder layer.

12. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
a second oxide layer which is an oxide containing boron and resides around the soft magnetic powder layer; and
a first oxide layer of an iron oxide residing around the second oxide layer, wherein:
the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface.

13. The soft magnetic powder according to claim 12 , wherein the iron oxide is FeO, Fe 2 O 3 , or Fe 3 O 4 .

14. A soft magnetic powder comprising:
a soft magnetic powder layer of an unoxidized soft magnetic material;
a second oxide layer as an oxide with iron or boron residing around the soft magnetic powder layer; and
a first oxide layer of an iron oxide residing around the second oxide layer, wherein:
the first oxide layer and the second oxide layer reside in a region of 20 nm or more and 500 nm or less from a surface of the soft magnetic powder, and are absent in a region of more than 500 nm and 1,600 nm or less from the surface, and
a total amount of surface oxygen of the first oxide layer and the second oxide layer is 6.81% by weight.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Maede Masato
• Fukuda Kazuto
• Kojima Toshiyuki
• Saitoh Mitsuo

Classifications

• B22F1/08

  Metallic powder characterised by particles having an amorphous microstructure · CPC title

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B22F1/16

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

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• H01F27/255

  made from particles (H01F27/26 takes precedence) · CPC title