Method of producing anisotropic magnetic powder

Patent metadata

Field	Value
Publication number	US-10867728-B2
Application number	US-201816227941-A
Country	US
Kind code	B2
Filing date	Dec 20, 2018
Priority date	Dec 22, 2017
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

The present invention relates to a method of producing an anisotropic magnetic powder having good magnetic properties. The method of producing an anisotropic magnetic powder includes: pretreating an oxide containing Sm and Fe by heat treatment in a reducing gas atmosphere to obtain a partial oxide; heat treating the partial oxide in the presence of a reductant at a first temperature of 1000° C. or higher and 1090° C. or lower and then at a second temperature lower than the first temperature and in the range of 980° C. or higher and 1070° C. or lower to obtain alloy particles; and nitriding the alloy particles to obtain an anisotropic magnetic powder.

First claim

What is claimed is:

1. A method of producing an anisotropic magnetic powder, comprising:
pretreating an oxide containing Sm and Fe by heat treatment in a reducing gas atmosphere to obtain a partial oxide;
heat treating the partial oxide in the presence of a reductant at a first temperature of 1000° C. or higher and 1090° C. or lower and then at a second temperature lower than the first temperature and in a range of 980° C. or higher and 1070° C. or lower to obtain alloy particles; and
nitriding the alloy particles to obtain an anisotropic magnetic powder,
wherein the heat treatment at the second temperature is performed for 10 minutes or more.

2. The method of producing an anisotropic magnetic powder according to claim 1 ,
wherein the second temperature is lower than the first temperature by 15° C. or more and 60° C. or less.

3. The method of producing an anisotropic magnetic powder according to claim 1 ,
wherein the heat treatment at the first temperature and the heat treatment at the second temperature are continuously performed.

4. The method of producing an anisotropic magnetic powder according to claim 1 ,
wherein the heat treatment at the first temperature is performed for less than 120 minutes.

5. The method of producing an anisotropic magnetic powder according to claim 1 , wherein the oxide containing Sm and Fe further contains La.

6. The method of producing an anisotropic magnetic powder according to claim 1 , wherein the oxide containing Sm and Fe further contains W.

7. The method of producing an anisotropic magnetic powder according to claim 1 , wherein the oxide containing Sm and Fe further contains Co.

Assignees

• Nichia Corp

Inventors

• Maehara Hisashi

Classifications

• B22F1/102

  Metallic powder coated with organic material · CPC title

• B22F1/142

  Thermal or thermo-mechanical treatment · CPC title

• C01B21/06 Primary

  Binary compounds of nitrogen with metals, with silicon, or with boron, {or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron}(azides C01B21/08) · CPC title

• H01F1/059 Primary

  and Va elements, e.g. Sm2Fe17N2 · CPC title

• B22F9/24

  starting from liquid metal compounds, e.g. solutions · CPC title