Anisotropic magnetic powders and method of producing the same

Patent metadata

Field	Value
Publication number	US-2017186519-A1
Application number	US-201615387997-A
Country	US
Kind code	A1
Filing date	Dec 22, 2016
Priority date	Dec 24, 2015
Publication date	Jun 29, 2017
Grant date	—

Abstract

A method of producing anisotropic magnetic powders comprising obtaining a precipitate containing an element R, iron and lanthanum from a solution including R, iron and lanthanum, wherein R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu; obtaining an oxide containing R, iron and lanthanum from the precipitate; treating the oxide with a reducing gas to obtain a partial oxide; obtaining alloy particles by reduction diffusion of the partial oxide at a temperature in the range of 920° C. to 1200° C.; and nitriding the alloy particles to produce an anisotropic magnetic powder represented by the following general formula: R v-x Fe (100-v-w-z) N w La x W z , where 3≦v−x≦30, 5≦w≦15, 0.08≦x≦0.3, and 0≦z≦2.5.

First claim

What is claimed is:

1 . A method of producing anisotropic magnetic powders comprising:
obtaining a precipitate containing an element R, iron and lanthanum from a solution including R, iron and lanthanum,
wherein R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu;
obtaining an oxide containing R, iron and lanthanum from the precipitate; treating the oxide with a reducing gas to obtain a partial oxide; obtaining alloy particles by reduction diffusion of the partial oxide at a temperature in the range of 920° C. to 1200° C.; and nitriding the alloy particles to produce an anisotropic magnetic powder represented by the following general formula:
R v-x Fe (100-v-w-z) N w La x W z
where 3≦v−x≦30, 5≦w≦15, 0.08≦x≦0.3, and 0≦z≦2.5.

2 . The method of producing anisotropic magnetic powders according to claim 1 , wherein the precipitate and the oxide further contain tungsten.

3 . The method of producing anisotropic magnetic powders according to claim 1 , wherein R is Sm.

4 . The method of producing anisotropic magnetic powders according to claim 1 , wherein x is in the range of 0.11≦x≦0.22.

5 . The method of producing anisotropic magnetic powders according to claim 1 , wherein x is in the range of 0.15≦x≦0.19.

6 . The method of producing anisotropic magnetic powders according to claim 1 , wherein in the obtaining alloy particles, the reduction diffusion of the partial oxide is performed at a temperature in the range of 950° C. to 1200° C.

7 . The method of producing anisotropic magnetic powders according to claim 1 , wherein the circularity of the anisotropic magnetic powder is not less than 0.5.

8 . The method of producing anisotropic magnetic powders according to claim 1 ,
wherein the anisotropic magnetic powder has an average particle size of not less than 3.5 μm and not more than 6.2 μm; wherein the anisotropic magnetic powder has a particle size D10 of not less than 1.6 μm and not more than 2.8 μm; wherein the anisotropic magnetic powder has a particle size D50 of not less than 3.5 μm and not more than 5.7 μm; wherein the anisotropic magnetic powder has a particle size D90 of not less than 6.0 μm and not more than 9.5 μm; and wherein the anisotropic magnetic powder has a span of not more than 1.25 according to the following equation:
Span=( D 90− D 10)/ D 50,

where D90 corresponds to 90%, D10 corresponds to 10%, and D50 corresponds to 50% in a cumulative particle size distribution.

9 . The method of producing anisotropic magnetic powders according to claim 1 , wherein the residual magnetic flux density is not less than 127 Am 2 /g and the coercive force is not less than 10 kOe when z=0.

10 . The method of producing anisotropic magnetic powders according to claim 1 , wherein the residual magnetic flux density is not less than 119 Am 2 /g, the coercive force is not less than 17 kOe, and the squareness ratio is not less than 6 kOe when z>0.

11 . An anisotropic magnetic powder represented by the following general formula:
R v-x Fe (100-v-w-z) N w La x W z where R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu, 3≦v−x≦30, 5≦w≦15, 0.08≦x≦0.3, and 0≦z≦2.5; wherein the anisotropic magnetic powder has an average particle size of not less than 3.5 μm and not more than 6.2 μm; wherein the anisotropic magnetic powder has a particle size D10 of not less than 1.6 μm and not more than 2.8 μm; wherein the anisotropic magnetic powder has a particle size D50 of not less than 3.5 μm and not more than 5.7 μm; wherein the anisotropic magnetic powder has a particle size D90 of not less than 6.0 μm and not more than 9.5 μm; and wherein the anisotropic magnetic powder has a span of not more than 1.25 according to the following equation:
Span=( D 90− D 10)/ D 50,

where D90 corresponds to 90%, D10 corresponds to 10%, and D50 corresponds to 50% in a cumulative particle size distribution.

12 . The anisotropic magnetic powder according to claim 11 , wherein x is in the range of 0.11≦x≦0.22.

13 . The anisotropic magnetic powder according to claim 11 , wherein x is in the range of 0.15≦x≦0.19.

14 . The anisotropic magnetic powder according to claim 11 , wherein the circularity is not less than 0.5.

15 . The anisotropic magnetic powder according to claim 11 , wherein R is Sm.

16 . The anisotropic magnetic powder according to claim 11 , wherein the residual magnetic flux density is not less than 127 Am 2 /g and the coercive force is not less than 10 kOe when z=0.

17 . The anisotropic magnetic powder according to claim 11 , wherein the residual magnetic flux density is not less than 119 Am 2 /g, the coercive force is not less than 17 kOe, and the squareness ratio is not less than 6 kOe when z>0.

Assignees

• Nichia Corp

Inventors

• Maehara Hisashi

Classifications

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F2304/10

  Micron size particles, i.e. above 1 micrometer up to 500 micrometer · CPC title

• H01F1/059 Primary

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

• B22F2303/01

  Main component · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title