Method of producing bonded magnet comprising SmFeN-based anisotropic magnetic powder

Patent metadata

Field	Value
Publication number	US-12406784-B2
Application number	US-202217806376-A
Country	US
Kind code	B2
Filing date	Jun 10, 2022
Priority date	Jun 10, 2021
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A method of producing a SmFeN-based anisotropic magnetic powder is provided, the method including preparing a SmFeN-based anisotropic magnetic powder before dispersing comprising Sm, Fe, W, and N, and dispersing the SmFeN-based anisotropic magnetic powder before dispersing using a resin-coated metal media or a resin-coated ceramic media to obtain a SmFeN-based anisotropic magnetic powder. Also provided is a SmFeN-based anisotropic magnetic powder comprising Sm, Fe, W, and N and having an average particle size of less than 2.5 μm, a residual magnetization σr of not less than 130 emu/g, and an oxygen content of not higher than 0.75% by mass.

First claim

What is claimed is:

1. A method of producing a bonded magnet, the method comprising:
preparing a SmFeN-based anisotropic magnetic powder before dispersing comprising Sm, Fe, W, and N, and
dispersing the SmFeN-based anisotropic magnetic powder using a resin-coated metal media or a resin-coated ceramic media to obtain a SmFeN-based anisotropic magnetic powder, and
mixing the SmFeN-based anisotropic magnet powder and a resin,
wherein the media has a diameter of at least 2 mm and not more than 100 mm.

2. The method according to claim 1 ,
wherein the media has a specific gravity of not less than 4.

3. The method according to claim 2 ,
wherein the media has a specific gravity of not more than 8.

4. The method-according to claim 1 ,
wherein the resin-coated metal media is a nylon resin-coated iron core media.

5. The method according to claim 1 ,
wherein the dispersing is performed by a vibration mill.

6. The method according to claim 5 ,
wherein, in the dispersing, an amount of the media is at least 60% by volume but not more than 70% by volume, and an amount of the SmFeN-based anisotropic magnetic powder before dispersing is at least 3% by volume but not more than 20% by volume, each relative to a volume of a container used to contain the SmFeN-based anisotropic magnetic powder and the media.

7. The method according to claim 1 ,
wherein the dispersing is performed in the absence of a solvent.

8. The method according to claim 1 ,
wherein the dispersing is performed in an inert gas atmosphere.

9. The method according to claim 1 ,
wherein the step of preparing the SmFeN-based anisotropic magnetic powder before dispersing includes:
pretreating an oxide comprising Sm, Fe, and W by heat treatment in a reducing gas-containing atmosphere to obtain a partial oxide;
heat treating the partial oxide in the presence of a reducing agent to obtain alloy particles;
nitriding the alloy particles to obtain a nitride; and
washing the nitride to obtain the SmFeN-based anisotropic magnetic powder before dispersing.

10. The method according to claim 1 ,
wherein the SmFeN-based anisotropic magnetic powder has D50 that is a particle size corresponding to 50th percentile of a cumulative particle size distribution by volume of the SmFeN-based anisotropic magnetic powder of at least 0.5 μm but not more than 2.5 μm.

11. A method of producing a bonded magnet, the method comprising:
preparing a SmFeN-based anisotropic magnetic powder before dispersing comprising Sm, Fe, W, and N, and
dispersing the SmFeN-based anisotropic magnetic powder using a resin-coated metal media or a resin-coated ceramic media to obtain a SmFeN-based anisotropic magnetic powder, and
mixing the SmFeN-based anisotropic magnet powder and a resin,
wherein the dispersing is performed by a vibration mill, and
wherein, in the dispersing, an amount of the media is at least 60% by volume but not more than 70% by volume, and an amount of the SmFeN-based anisotropic magnetic powder before dispersing is at least 3% by volume but not more than 20% by volume, each relative to a volume of a container used to contain the SmFeN-based anisotropic magnetic powder and the media.

12. The method according to claim 11 ,
wherein the media has a specific gravity of not less than 4.

13. The method according to claim 11 ,
wherein the media has a specific gravity of not more than 8.

14. The method-according to claim 11 ,
wherein the resin-coated metal media is a nylon resin-coated iron core media.

15. The method according to claim 11 ,
wherein the dispersing is performed in the absence of a solvent.

16. The method according to claim 11 ,
wherein the dispersing is performed in an inert gas atmosphere.

17. The method according to claim 11 ,
wherein the step of preparing the SmFeN-based anisotropic magnetic powder before dispersing includes:
pretreating an oxide comprising Sm, Fe, and W by heat treatment in a reducing gas-containing atmosphere to obtain a partial oxide;
heat treating the partial oxide in the presence of a reducing agent to obtain alloy particles;
nitriding the alloy particles to obtain a nitride; and
washing the nitride to obtain the SmFeN-based anisotropic magnetic powder before dispersing.

18. The method according to claim 11 ,
wherein the SmFeN-based anisotropic magnetic powder has D50 that is a particle size corresponding to 50th percentile of a cumulative particle size distribution by volume of the SmFeN-based anisotropic magnetic powder of at least 0.5 μm but not more than 2.5 μm.

Assignees

• Nichia Corp

Inventors

• Maehara Hisashi

Classifications

• C22C38/005

  containing rare earths, i.e. Sc, Y, Lanthanides · CPC title

• C22C33/0235

  Starting from compounds, e.g. oxides · CPC title

• C22C2202/02

  Magnetic · CPC title

• C22C38/001 Primary

  containing N · CPC title

• H01F1/059 Primary

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