Method of increasing anisotropy of magnetic materials

Patent metadata

Field	Value
Publication number	US-2024290538-A1
Application number	US-202418585633-A
Country	US
Kind code	A1
Filing date	Feb 23, 2024
Priority date	Feb 24, 2023
Publication date	Aug 29, 2024
Grant date	—

Abstract

A method of increasing anisotropy of magnetic materials formed by a hydrogenation-disproportionation-desorption-recombination (HDDR) process is provided. The method includes subjecting a starting magnetic material to a hydrogenation-disproportionation (HD) step in the presence of a magnetic field to obtain intermediate materials. The strength of the applied magnetic field is between 0.25 T and 9 T, optionally less than or equal to 2 T. The HD step may be performed for a period of time between 10 and 60 minutes at a temperature of at least 600° C., optionally in the range of 600° C. to 900° C. Subsequently, the intermediate materials are subjected to a desorption-recombination (DR) step to obtain a magnetic powder. Application of the magnetic field during the hydrogenation-disproportionation step increases the magnetic anisotropy of the obtained magnetic powder. Magnetic powders obtained by the method and bonded magnets formed with the magnetic powders are also provided.

First claim

What is claimed is:

1 . A method of increasing anisotropy of magnetic materials formed by a hydrogenation-disproportionation-desorption-recombination (HDDR) process, the method comprising:
providing a starting magnetic material; subjecting the starting magnetic material to a hydrogenation-disproportionation (HD) step in the presence of a magnetic field to obtain intermediate materials; and subsequently subjecting the intermediate materials to a desorption-recombination (DR) step to obtain a magnetic powder; whereby application of the magnetic field during the hydrogenation-disproportionation step increases the magnetic anisotropy of the obtained magnetic powder.

2 . The method of claim 1 , wherein the strength of the applied magnetic field is between 0.25 T and 9 T.

3 . The method of claim 2 , wherein the strength of the applied magnetic field is less than or equal to 2 T.

4 . The method of claim 1 , wherein the hydrogenation-disproportionation step is performed for a period of time between approximately 10 and 60 minutes.

5 . The method of claim 1 , wherein the hydrogenation-disproportionation step includes heating the starting magnetic material to a temperature of at least 600° C. in the presence of hydrogen gas.

6 . The method of claim 5 , wherein the temperature is in a range of 600° C. to 900° C.

7 . The method of claim 1 , wherein the magnetic field is also applied during the desorption-recombination step.

8 . The method of claim 1 , wherein the starting magnetic material is a compound including one of the following chemical compositions: (RE) 2 (TM) 14 X; (RE)(TM) 5 ; (RE) 2 (TM) 17 ; (RE) 5 (TM) 17 ; (RE)(TM) 2 ; (RE)(TM) 3 ; (RE) 6 (TM) 23 ; (RE) 2 (TM) 7 ; (RE) 5 (TM) 19 ; (RE)(TM) 12 ; (RE) 3 (TM) 27 ; (RE)(TM) 4 X; (RE)(TM) 12 X 6 ; (RE) 2 (TM) 23 X 3 ; (RE) 5 (TM) 9 X; (RE) 2 (TM) 5 X 2 ; (RE) 2 (TM) 7 X 3 ; (RE) 2 (TM) 17 X 3 ; (RE) 3 (TM) 11 X 4 ; (RE) 3 (TM) 13 X 2 , (RE) 5 (TM) 19 X 6 ; wherein RE is a rare earth metal component, TM is a transition metal component, and X is a nonmetal component including boron or nitrogen.

9 . A method of increasing anisotropy of magnetic materials formed by a hydrogenation-disproportionation-desorption-recombination (HDDR) process, the method comprising:
providing a starting magnetic material; disposing the starting magnetic material in an inert atmosphere; subjecting the starting magnetic material to a hydrogenation-disproportionation (HD) step in the presence of an applied static magnetic field, the hydrogenation-disproportionation step including:
heating the starting magnetic material to a first temperature and introducing a concentration of hydrogen gas to the starting magnetic material for a first period of time to obtain intermediate materials; and
subsequently subjecting the intermediate materials to a desorption-recombination (DR) step, the desorption-recombination step including:
purging the hydrogen gas, heating the intermediate materials to a second temperature under vacuum, maintaining the second temperature for a second period of time under vacuum to obtain a magnetic powder, and allowing the magnetic powder to cool;
whereby application of the static magnetic field during the hydrogenation-disproportionation step increases the magnetic anisotropy of the obtained magnetic powder.

10 . The method of claim 9 , wherein the strength of the applied magnetic field is between 0.25 T and 9 T.

11 . The method of claim 10 , wherein the strength of the applied magnetic field is less than or equal to 2 T.

12 . The method of claim 9 , wherein the desorption-recombination step further includes applying the static magnetic field.

13 . The method of claim 9 , wherein the first temperature is in a range of 600° C. to 900° C.

14 . The method of claim 9 , wherein the first period of time is in a range of 10 to 60 minutes.

15 . The method of claim 9 , wherein the second temperature is approximately equal to or greater than the first temperature.

16 . The method of claim 9 , wherein the second period of time is at least 30 minutes.

17 . The method of claim 9 , wherein prior to the desorption-recombination step, the intermediate materials obtained in the hydrogenation-disproportionation step are cooled to ambient temperature.

18 . The method of claim 9 , wherein the starting magnetic material is a compound including one of the following chemical compositions: (RE) 2 (TM) 14 X; (RE)(TM) 5 ; (RE) 2 (TM) 17 ; (RE) 5 (TM) 17 ; (RE)(TM) 2 ; (RE)(TM) 3 ; (RE) 6 (TM) 23 ; (RE) 2 (TM) 7 ; (RE) 5 (TM) 19 ; (RE)(TM) 12 ; (RE) 3 (TM) 27 ; (RE)(TM) 4 X; (RE)(TM) 12 X 6 ; (RE) 2 (TM) 23 X 3 ; (RE) 5 (TM) 9 X; (RE) 2 (TM) 5 X 2 ; (RE) 2 (TM) 7 X 3 ; (RE) 2 (TM) 17 X 3 ; (RE) 3 (TM) 11 X 4 ; (RE) 3 (TM) 13 X 2 , (RE) 5 (TM) 19 X 6 ; wherein RE is a rare earth metal component, TM is a transition metal component, and X is a nonmetal component including boron or nitrogen.

19 . The method of claim 9 , wherein the starting magnetic material is a compound including both a rare earth metal component (RE) and a transition metal component (TM), the starting magnetic material having the chemical formula Nd 2-x (RE) x Fe 14-y (TM) y B, wherein: RE is one of La, Ce, Pr, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and Y; TM is one of Fe and Co; 0≤x≤2; and 0≤y≤14.

20 . The method of claim 19 , wherein the starting magnetic material includes Nd 2 Fe 14 B.

21 . A magnetic powder obtained by the method of claim 1 .

22 . A magnetic powder obtained by the method of claim 9 .

23 . A magnet formed with the magnetic powder of claim 21 , wherein the magnet is one of a bonded magnet, a sintered magnet, or a powder-in-tube magnet.

24 . A magnet formed with the magnetic powder of claim 22 , wherein the magnet is one of a bonded magnet, a sintered magnet, or a powder-in-tube magnet.

Assignees

• Ut Battelle Llc
• Univ Iowa State Res Found Inc

Inventors

• Kesler Michael S
• Mcguire Michael A
• Tener Zack
• Kramer Matthew J
• Liu Xubo
• Nlebedim Cajetan Ikenna

Classifications

• C22C2202/02

  Magnetic · CPC title

• B22F9/023

  Hydrogen absorption · CPC title

• H01F41/0273 Primary

  Imparting anisotropy (methods and devices for magnetising permanent magnets H01F13/003) · CPC title

• H01F1/0573 Primary

  obtained by reduction or by hydrogen decrepitation or embrittlement · CPC title

• B22F2201/10

  Inert gases · CPC title