Rare earth-bonded magnetic powder and preparation method therefor, and bonded magnet

Patent metadata

Field	Value
Publication number	US-11495376-B2
Application number	US-201816612294-A
Country	US
Kind code	B2
Filing date	Jun 20, 2018
Priority date	Nov 29, 2017
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

The present invention discloses rare earth-bonded magnetic powder and a preparation method therefor. The bonded magnetic powder is of a multilayer core-shell structure, and comprises a core layer and an antioxidant layer ( 3 ), wherein the core layer is formed by RFeMB, R is Nd and/or PrNd, and M is one or more of Co, Nb, and Zr; and the core layer is coated with an iron-nitrogen layer ( 2 ). In addition, the present invention also discloses the preparation method for the rare earth-bonded magnetic powder and a bonded magnet. The oxidation and corrosion of magnetic raw powder during phosphorization and subsequent treatment process are effectively prevented, thereby further improving the long-term temperature resistance and environmental tolerance of the material.

First claim

What is claimed is:

1. Rare earth-bonded magnetic powder, wherein the bonded magnetic powder is of a multilayer core-shell structure and comprises a core layer and an antioxidant layer, wherein the core layer is formed by RFeMB, R is Nd and/or PrNd, and M is one or more of Co, Nb, and Zr; and the core layer is externally coated with an iron-nitrogen layer and the antioxidant layer in sequence.

2. The rare earth-bonded magnetic powder according to claim 1 , wherein in the RFeMB, the content of R is 20-30 wt %, the content of M is 0-6 wt % (excluding 0), the content of B is 0.85-1.05 wt %, and the balance is Fe.

3. The rare earth-bonded magnetic powder according to claim 1 , wherein the iron-nitrogen layer is formed by an iron-nitrogen compound and has a thickness of 50-500 nm.

4. The rare earth-bonded magnetic powder according to claim 1 , wherein the antioxidant layer is formed by a phosphate composite and has a thickness of 10-200 nm.

5. A preparation method for the rare earth-bonded magnetic powder according to any one of claim 1 , wherein the preparation method comprises the following steps: performing surface nitriding treatment on magnetic raw powder to obtain nitrided powder, wherein the nitriding temperature is 300-550° C., and the time is 10-120 min;
preparing an antioxidant solution; and immersing the nitrided powder in the antioxidant solution and performing drying to obtain the bonded magnetic powder of a core-shell structure.

6. The method according to claim 5 , wherein the nitriding treatment is the reaction between the magnetic raw powder and a nitrogen-containing atmosphere.

7. The method according to claim 6 , wherein the nitrogen-containing atmosphere is mainly formed by nitrogen without containing ammonia and hydrogen.

8. The method according to claim 5 , wherein the antioxidant solution is a solution formed by dissolving phosphoric acid or a salt thereof in an organic solvent, and the ratio of the antioxidant to the organic solvent is (0.1-5)g:100 ml.

9. The method according to claim 5 , wherein the drying temperature is 80-110° C.

10. A bonded magnet, comprising the rare earth-bonded magnetic powder according to claim 1 .

11. The method according to claim 5 , wherein in the RFeMB, the content of R is 20-30 wt %, the content of M is 0-6 wt % (excluding 0), the content of B is 0.85-1.05 wt %, and the balance is Fe.

12. The method according to claim 5 , wherein the iron-nitrogen layer is formed by an iron-nitrogen compound and has a thickness of 50-500 nm.

13. The method according to claim 5 , wherein the antioxidant layer is formed by a phosphate composite and has a thickness of 10-200 nm.

14. The method according to claim 10 , wherein in the RFeMB, the content of R is 20-30 wt %, the content of M is 0-6 wt % (excluding 0), the content of B is 0.85-1.05 wt %, and the balance is Fe.

15. The method according to claim 10 , wherein the iron-nitrogen layer is formed by an iron-nitrogen compound and has a thickness of 50-500 nm.

16. The method according to claim 10 , wherein the antioxidant layer is formed by a phosphate composite and has a thickness of 10-200 nm.

17. The rare earth-bonded magnetic powder according to claim 3 , wherein the iron-nitrogen layer is formed by an iron-nitrogen compound and has a thickness of 150-350 nm.

18. The rare earth-bonded magnetic powder according to claim 3 , wherein the iron-nitrogen layer is formed by an iron-nitrogen compound and has a thickness of 200-300 nm.

19. The rare earth-bonded magnetic powder according to claim 4 , wherein the antioxidant layer is formed by a phosphate composite and has a thickness of 20-160 nm.

20. The rare earth-bonded magnetic powder according to claim 4 , wherein the antioxidant layer is formed by a phosphate composite and has a thickness of 50-80 nm.

Assignees

• Grirem Advanced Mat Co Ltd
• Guoke Re Advanced Mat Co Ltd

Inventors

• Luo Yang
• Zhang Hongbin
• Hu Zhou
• Yu Dunbo
• Quan Ningtao
• Yang Yuanfei
• Yan Wenlong
• Xie Jiajun

Classifications

• B22F1/16 Primary

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• C22C38/14

  containing titanium or zirconium · CPC title

• H01F41/02

  for manufacturing cores, coils, or magnets (H01F41/14 takes precedence; for dynamo-electric machines H02K15/00) · CPC title

• C22C38/001

  containing N · CPC title

• Y10T428/12181

  Composite powder [e.g., coated, etc.] · CPC title