# US 12,119,151 B2 · Ferrite powder and method of producing the same

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- Number: US 12,119,151 B2
- Document ID: US12119151B2
- Status: Granted
- Kind: B2
- Application number: 17/795,382
- Filed: 2021-01-27
- Published: 2023-03-23
- Granted: 2024-10-15
- Earliest claimed: 2020-01-27
- Assignees: Powdertech Co., Ltd.
- Applicants: Powdertech Co., Ltd.
- Inventors: Koji Aga; Takashi Kojima; Takao Sugiura; Sho Kuwahara; Satomi Konno; Tadashi Tsuduki
- Web page: https://patentgrep.com/patent/US12119151B2

## CPC

- H01F 1/344: {Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4}
- C01G 49/0072: {containing manganese}
- C01P 2002/50: Solid solutions
- C01P 2004/32: Spheres
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/11: Powder tap density
- C01P 2006/12: Surface area
- C01P 2006/40: Electric properties
- C01P 2006/42: Magnetic properties
- C01P 2006/80: Compositional purity
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

Provided are a ferrite powder capable of maintaining a high withstand voltage even when used in a resin composition having high magnetic properties and electrical resistivity and a high filling ratio, and a method for producing the same. A ferrite powder composed of spherical ferrite particles, wherein the ferrite powder contains iron (Fe): 55.0-70.0 mass % and manganese (Mn): 3.5-18.5 mass %, the ferrite powder containing more than 0.0 mass % to 7.5 mass % α-Fe2O3, and the ferrite powder has a volume average particle size (D50) of 15.0 μm or less.

## Claims

### Claim 1

A ferrite powder comprising highly spherical ferrite particles,
wherein the ferrite powder contains 55.0 to 70.0 mass % iron (Fe) and 3.5 to 18.5 mass % manganese (Mn), the ferrite powder containing more than 0.0 mass % to 7.5 mass % α-Fe2O3,
wherein the ferrite powder has a volume average particle size (D50) of 15.0 μm or less,
wherein the content of elements other than iron (Fe), manganese (Mn), and oxygen (O) in the ferrite powder is 0.5 mass % or less, and
wherein the ferrite powder has a carbon (C) content of from 0.001 mass % to 0.12 mass %.

### Claim 2 (depends on 1)

The ferrite powder according to claim 1, wherein the α-Fe2O3 is contained in the ferrite powder in an amount of 3.0 mass % to 6.0 mass %.

### Claim 3 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder has a volume average particle size (D50) of 2.0 μm to 15 μm.

### Claim 4 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder has a mean shape factor SF-1 of 100 to 110.

### Claim 5 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder has a volume resistivity of 1.0×108 Ω·cm or more.

### Claim 6 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder contains 58.0 to 69.0 mass % iron (Fe) and 6.0 to 10.0 mass % manganese (Mn).

### Claim 7 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder has a volume average particle size (D50) of 2.5 to 7.0 μm.

### Claim 8 (depends on 1)

The ferrite powder according to claim 1, wherein the ferrite powder comprises one or more compounds selected from the group consisting of erucic acid amide (C22H43NO), butyl palmitate (C20H40O2) and butyl stearate (C22H44O2).

### Claim 9 (depends on 1)

The ferrite powder according to claim 1, wherein the α-Fe2O3 is dispersed inside the highly spherical ferrite particles.

### Claim 10 (depends on 1)

A process for producing the ferrite powder according to claim 1, comprising the steps of:
mixing raw materials for ferrite to prepare a raw material mixture;
calcining the raw material mixture to form a calcined product;
pulverizing and granulating the calcined product to prepare a granular product; and
thermally spraying the granular product to produce a thermally sprayed product;
wherein the granular product has a carbon content of 0.001 to 0.095 mass %, and the feed rate of a raw material is 2.5 to 9.0 kg/hour, the flow rate of combustible gas is 3 to 10 m3/hour, and the flow rate of oxygen is 18 to 60 m3/hour in the step of thermally spraying.