Soft magnetic metal powder-compact magnetic core and reactor

Patent metadata

Field	Value
Publication number	US-9601249-B2
Application number	US-201615008872-A
Country	US
Kind code	B2
Filing date	Jan 28, 2016
Priority date	Feb 2, 2015
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The objective is to provide a soft magnetic metal powder-compact magnetic core and a reactor with an excellent DC superposition characteristic. The soft magnetic metal powder-compact magnetic core contains a soft magnetic metal powder, boron nitride and a silicon compound, when its section is ground and then observed, the ratio of the area occupied by the soft magnetic metal powder to that of the section of the soft magnetic metal powder-compact magnetic core is 90% or more and 95% or less, and a roundness of the section of 80% or more of the particles constituting the soft magnetic metal powder is 0.75 or more and 1.0 or less, and boron nitride exists in 70% or more of the voids-among-multiple-particles among the voids-among-multiple-particles in the section of the soft magnetic metal powder-compact magnetic core. Thus, the soft magnetic metal powder-compact magnetic core with an excellent DC superposition characteristic can be obtained.

First claim

What is claimed is:

1. A soft magnetic metal powder-compact magnetic core, comprising a soft magnetic metal powder, boron nitride and a silicon compound,
wherein, when a section of the soft magnetic metal powder-compact magnetic core is ground and then observed, a ratio of an area occupied by the soft magnetic metal powder to that of the section of the soft magnetic metal powder-compact magnetic core is 90% or more and 95% or less, and
a roundness in the section of 80% or more of particles constituting the soft magnetic metal powder is 0.75 or more and 1.0 or less, and
boron nitride exists in 70% or more of voids-among-multiple-particles in the section of the soft magnetic metal powder-compact magnetic core.

2. The soft magnetic metal powder-compact magnetic core of claim 1 , wherein,
the silicon compound is derived from silicone resin and comprises silicon (Si), oxygen (O) and carbon (C).

3. The soft magnetic metal powder-compact magnetic core of claim 1 , wherein,
0.17 mass % or more and 0.80 mass % or less of boron (B) and 0.22 mass % or more and 1.00 mass % or less of nitrogen (N) are contained in the soft magnetic metal powder-compact magnetic core.

4. The soft magnetic metal powder-compact magnetic core of claim 1 , wherein,
in a particle size distribution of the soft magnetic metal powder, when a particle diameter at which a number cumulated from a small side reaches 50% is defined as d50%, d50% is 30 μm or more and 60 μm or less.

5. The soft magnetic metal powder-compact magnetic core of claim 1 , wherein,
when the section of the soft magnetic metal powder-compact magnetic core is ground and then observed, it has a structure that one of the particles constituting the soft magnetic metal powder faces at least one adjacent particle at a region where no boron nitride exists.

6. A reactor prepared by using the soft magnetic metal powder-compact magnetic core of claim 1 .

Assignees

• Tdk Corp

Inventors

• Taniguchi Yusuke
• Kuroda Tomofumi
• Sakurai Yu

Classifications

• C22C30/00

  Alloys containing less than 50% by weight of each constituent · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• H01F1/24

  the particles being insulated · CPC title

• H01F1/1475

  the particles being insulated · CPC title

• H01F3/08 Primary

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