MAGNETIC CORE AND COIL COMPONENT

• US 20200135371A1
• Filed: 10/25/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: TONOYAMA, Kyohei, SATOH, Ken, SAITO, Kentaro, ASAI, Miyuki, OHKUBO, Hitoshi
• Granted Patent: US 11,183,320 B2
• Time in Patent Office: Days
• CPC Class Codes: B22F 1/05 Metallic powder characterised by the size or surface area of the particles
• CPC Class Codes: B22F 1/052 characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 1/07 Metallic powder characterised by particles having a nanoscale microstructure nanosized particles B22F1/054
• CPC Class Codes: B22F 1/16 Metallic particles coated with a non-metal coated with lubricating or binding agents or with organic material B22F1/10
• CPC Class Codes: B22F 2301/355 Rare Earth - Fe intermetallic alloys
• CPC Class Codes: B22F 2304/10 Micron size particles, i.e. above 1 micrometer up to 500 micrometer
• CPC Class Codes: C22C 2200/04 Nanocrystalline
• CPC Class Codes: C22C 2202/02 Magnetic
• CPC Class Codes: C22C 33/0278 with at least one alloying element having a minimum content above 5%
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/005 containing rare earths, i.e. Sc, Y, Lanthanides
• CPC Class Codes: C22C 38/08 containing nickel C22C38/105 takes precedence
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/16 containing copper
• CPC Class Codes: H01F 1/20 in the form of particles, e.g. powder H01F1/147 takes precedence
• CPC Class Codes: H01F 1/24 the particles being insulated

Abstract

A magnetic core includes a metal magnetic powder, which has a large size powder, an intermediate size powder, and a small size powder. A particle size of the large size powder is 10 μm or more and 60 μm or less. A particle size of the intermediate size powder is 2.0 μm or more and less than 10 μm. A particle size of the small size powder is 0.1 μm or more and less than 2.0 μm. The large size powder, the intermediate size powder, and the small size powder have an insulation coating. When A1 represents an average insulation coating thickness of the large size powder, A2 represents an average insulation coating thickness of the intermediate size powder, A3 represents an average insulation coating thickness of the small size powder, A3 is 30 nm or more and 100 nm or less, A3/A1≥1.3, and A3/A2≥1.0.

Claims

1. A magnetic core comprising a metal magnetic powder, in which

the metal magnetic powder has a large size powder, an intermediate size powder, and a small size powder,

a particle size of the large size powder is 10 μ

m or more and 60 μ

m or less,

a particle size of the intermediate size powder is 2.0 μ

m or more and less than 10 μ

m,

a particle size of the small size powder is 0.1 μ

m or more and less than 2.0 μ

m,

the large size powder, the intermediate size powder, and the small size powder have an insulation coating, and

when A1 represents an average insulation coating thickness of the large size powder, A2 represents an average insulation coating thickness of the intermediate size powder, A3 represents an average insulation coating thickness of the small size powder, A3 is 30 nm or more and 100 nm or less, A3/A1≥

1.3 is satisfied, and A3/A2≥

1.0 is satisfied.

2. The magnetic core according to claim 1, wherein the small size powder includes a permalloy.

3. The magnetic core according to claim 1, wherein a ratio of the large size powder existing with respect to the metal magnetic powder is 39% or more and 86% or less in terms of an area ratio in a cross section of the magnetic core.

4. The magnetic core according to claim 1, wherein A1≥

10 nm and A2≥

10 nm are satisfied.

5. The magnetic core according to claim 1, wherein A3 is 40 nm or more and 80 nm or less.

6. The magnetic core according to claim 1, wherein the metal magnetic powder includes a Fe-based nano crystal.

7. The magnetic core according to claim 1, wherein a ratio of the intermediate size powder existing with respect to the metal magnetic powder is 8% or more and 39% or less in terms of an area ratio in a cross section of the magnetic core.

8. The magnetic core according to claim 1, wherein the insulation coating is a coating film including a glass made of SiO₂ or a phosphate chemical conversion coating including phosphate.

9. The magnetic core according to claim 1 including a metal magnetic powder including the nano crystal and also a metal magnetic powder which does not include the nano crystal as the metal magnetic powder, and a ratio of the metal magnetic powder including the nano crystal with respect to entire magnetic metal powder is 40 wt % to 90 wt % in terms of a weight ratio.

10. A coil component having the magnetic core according to claim 1 and a coil.