# US 10,872,716 B2 · Soft magnetic flaky powder and method for producing the same

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- Number: US 10,872,716 B2
- Document ID: US10872716B2
- Status: Granted
- Kind: B2
- Application number: 15/525,422
- Filed: 2015-11-09
- Published: 2017-11-09
- Granted: 2020-12-22
- Earliest claimed: 2014-11-10
- Assignees: Sanyo Special Steel Co., Ltd.
- Applicants: Sanyo Special Steel Co., Ltd.
- Inventors: Fumihiro Maezawa; Toshiyuki Sawada
- Web page: https://patentgrep.com/patent/US10872716B2

## CPC

- B22F 9/04: starting from solid material, e.g. by crushing, grinding or milling ({C22C1/1084 takes precedence}; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C)
- B22F 1/068: Flake-like particles
- B22F 9/082: {atomising using a fluid (using centrifugal force B22F9/10)}
- C21D 6/002: {containing Cr (C21D6/004 takes precedence)}
- C21D 6/008: {containing Si}
- C22C 38/02: containing silicon
- C22C 38/18: containing chromium
- C22C 38/34: with more than 1.5% by weight of silicon
- H01F 1/14766: {Fe-Si based alloys}
- H01F 1/14775: {in the form of sheets}
- H01F 41/02: for manufacturing cores, coils, or magnets (H01F41/14 takes precedence; for dynamo-electric machines H02K15/00)
- B22F 2998/10: Processes characterised by the sequence of their steps
- C22C 2202/02: Magnetic
- H01F 1/147: Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)}
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

In order to provide a soft magnetic flaky powder that is used primarily in a member for an RFID and that has the high real part μ′ of a magnetic permeability and the low imaginary part μ″ of the magnetic permeability even when having an average particle diameter of 30 μm or more, and a method for producing the soft magnetic flaky powder, the present invention provides a soft magnetic flaky powder obtained by flattening-treatment of a soft magnetic powder, in which an average particle diameter is more than 30 μm, a coercive force measured by applying a magnetic field in the longitudinal direction of the flaky powder is in a range of 240 to 640 A/m, a saturation magnetization is 1.0 T or more, and an aspect ratio is 30 or more, and a method for producing the soft magnetic flaky powder.

## Claims

### Claim 1

A soft magnetic flaky powder obtained by flattening-treatment of a soft magnetic powder, wherein an average particle diameter D50 is more than 30 μm, a coercive force Hc measured by applying a magnetic field in the longitudinal direction of the flaky powder is in a range of 240 to 640 A/m, a saturation magnetization is 1.0 T or more, and an aspect ratio is 30 or more,
wherein the soft magnetic flaky powder comprises an Fe—Si—Cr alloy comprising Si: 15 mass % or less excluding zero, Cr: from more than 6 mass % to 18 mass %, and the balance of Fe with unavoidable impurities, and
wherein the soft magnetic flaky powder has a real magnetic permeability μ′ of 45 or more and an imaginary magnetic permeability μ″ of 1 or less, which are magnetic properties in an RFID use or a 13.56 MHz band.

### Claim 2 (depends on 1)

A method for producing the soft magnetic flaky powder of claim 1, comprising implementing a raw powder production step and a flattening-processing step of flattening the raw powder, thereby obtaining the soft magnetic flaky powder.

### Claim 3 (depends on 1)

A method for producing the soft magnetic flaky powder of claim 1, comprising implementing a raw powder production step using a gas atomization method or a disk atomization method, a flattening-processing step of flattening the raw powder, and a heat-treating step of heating the flattening-processed powder in a vacuum or argon atmosphere at 500° C. to 900° C., thereby obtaining the soft magnetic flaky powder.