Flat soft magnetic powder and production method therefor

Patent metadata

Field	Value
Publication number	US-10804014-B2
Application number	US-201715445270-A
Country	US
Kind code	B2
Filing date	Feb 28, 2017
Priority date	Mar 1, 2016
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

Provided is a flaky soft magnetic powder composed of an Fe—Si—Al alloy containing Si: 5.5 to 10.5 mass %, Al: 4.5 to 8.0 mass %, and Fe and incidental impurities: balance, wherein the flaky powder exhibits a ratio (D 50 /TD) of 35 to 92 where D 50 represents the average particle size (μm) of the powder and TD represents the tap density (Mg/m 3 ) of the powder, and the flaky powder exhibits a coercive force of 239 to 479 A/m as measured under application of a magnetic field in an in-plane direction of the flaky powder. The flaky soft magnetic powder exhibits superior sheet formability and has high magnetic permeability.

First claim

The invention claimed is:

1. A flaky soft magnetic powder comprising an Fe—Si—Al alloy containing Si: 5.5 to 10.5 mass %, Al: 5.5 to 8.0 mass %, and Fe and incidental impurities: balance, wherein the flaky powder exhibits a ratio (D 50 /TD) of 40 to 92 where D 50 represents the average particle size (μm) of the powder and TD represents the tap density (Mg/m 3 ) of the powder, and the flaky powder exhibits a coercive force of 239 to 479 A/m as measured under application of a magnetic field in an in-plane direction of the flaky powder.

2. The flaky soft magnetic powder according to claim 1 , wherein the coercive force as measured under application of a magnetic field in a thickness direction of the flaky powder is 2 to 4.5 times the coercive force as measured under application of a magnetic field in an in-plane direction of the flaky powder.

3. The flaky soft magnetic powder according to claim 1 , wherein the flaky powder exhibits a half width of the strongest XRD peak (2θ=44±2°) of 0.3 to 0.6°.

4. A method of producing the flaky soft magnetic powder according to claim 1 , the method comprising the steps of:
preparing a raw material powder by any process selected from water atomization, gas atomization, disk atomization, and grinding after melt-alloying;
flattening the raw material powder; and
heat-treating the flattened powder at 200 to 500° C. under vacuum or in an argon or nitrogen atmosphere.

5. The flaky soft magnetic powder according to claim 1 , wherein the flaky powder exhibits a ratio (D 50 /TD) of 55 to 92.

Assignees

• Sanyo Special Steel Co Ltd

Inventors

• KUSE Tetsuji
• Miura Kodai
• MAEZAWA Fumihiro
• Sawada Toshiyuki

Classifications

• B22F1/068

  Flake-like particles · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F2009/0848

  Melting process before atomisation · CPC title

• H01F1/14791 Primary

  Fe-Si-Al based alloys, e.g. Sendust · CPC title

• B22F9/10

  using centrifugal force · CPC title