Material for anisotropic magnet and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9324485-B2
Application number	US-68312510-A
Country	US
Kind code	B2
Filing date	Jan 6, 2010
Priority date	Feb 29, 2008
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A material for anisotropic magnet, comprising,
(1) a Pr-T-B—Ga-based composition containing Pr: 12.5 to 15.0 atomic percent, B: 4.5 to 6.5 atomic percent, Ga: 0.1 to 0.7 atomic percent, and the balance of T and inevitable impurities, wherein T is Fe or obtained by substituting Co for a portion of the Fe; and having, (2) a degree of magnetic alignment of 0.92 or more, wherein the degree of magnetic alignment is defined by remanence (Br)/saturation magnetization (Js); and (3) a crystal grain diameter of 1 μm or less.

First claim

What is claimed is:

1. A hot plastically deformed anisotropic magnet having aligned axes of easy magnetization of crystal grains of the magnet, the anisotropic magnet comprising:
(1) a T-based composition consisting of R, B, Ga, and a balance of T and inevitable impurities, wherein R is Pr or Pr that is optionally substituted with at least one element selected from the group consisting of Nd, Dy, and Tb;
wherein an amount of R is 12.5 to 15 atomic percent;
an amount of B is 4.5 to 6.5 atomic percent; and
an amount of Ga is 0.1 to 0.7 atomic percent;
wherein T is Fe or Fe partially substituted with Co, and having
(2) a degree of magnetic alignment of 0.92 or more, wherein the degree of magnetization is defined by remanence (Br) / saturation magnetization (Js), wherein the remanence (Br) is 1.20 T or more, and a coercivity is 1600 kA/m or more; and
(3) flattened crystal grains having a crystal grain diameter of 1 μm or less, and wherein R contains at least 50 atomic percent of Pr.

2. A hot plastically deformed anisotropic magnet having aligned axes of easy magnetization of crystal grains of the magnet, the anisotropic magnet comprising
(1) a T-based composition consisting of R, B, Ga, at least one element selected from the group consisting of Cu and Al, and a balance of T and inevitable impurities, wherein R is Pr or Pr that is optionally substituted with at least one element selected from the group consisting of Nd, Dy, and Tb;
wherein an amount of R is 12.5 to 15 atomic percent;
an amount of B is 4.5 to 6.5 atomic percent; and
an amount of Ga is 0.1 to 0.7 atomic percent;
wherein T is Fe or Fe partially substituted with Co, and having (2) a degree of magnetic alignment of 0.92 or more, wherein the degree of magnetization is defined by remanence (Br) / saturation magnetization (Js), wherein the remanence is 1.20 T or more, and a coercivity is 1600 kA/m or more; and
(3) flattened crystal grains having a crystal grain diameter of 1 μm or less,
and wherein R contains at least 50 atomic percent of Pr.

3. A method of manufacturing a magnet comprising:
dissolving an alloy to form a molten alloy;
rapidly-quenching the molten alloy forming a ribbon;
pulverizing the ribbon to form an alloy powder;
cold-pressing the alloy powder to form a cold-pressed body;
pre-heating the cold-pressed body under a temperature of 500° C. to 850° C. to obtain a pre-heated cold-pressed body;
hot-forming the pre-heated cold-pressed body to obtain a hot-formed body; and
performing a hot plastic deforming to the hot-formed body to form an anisotropic magnet according to claim 1 .

4. A method of manufacturing a magnet comprising:
dissolving an alloy to form a molten alloy;
rapidly-quenching the molten alloy forming a ribbon;
pulverizing the ribbon to form an alloy powder;
cold-pressing the alloy powder to form a cold-pressed body;
pre-heating the cold-pressed body under a temperature of 500° C. to 850° C. to obtain a pre-heated cold-pressed body;
hot-forming the pre-heated cold-pressed body to obtain a hot-formed body; and
performing a hot plastic deforming to the hot-formed body to form an anisotropic magnet according to claim 2 .

5. The hot plastically deformed anisotropic magnet according to claim 1 , wherein R is Pr.

6. The hot plastically deformed anisotropic magnet according to claim 1 , wherein an axis of easy magnetization of a R 2 Fe 14 B crystal is aligned.

7. The hot plastically deformed anisotropic magnet according to claim 1 , wherein the alloy powder is in a flake form composed of fine crystal grains.

8. The hot plastically deformed anisotropic magnet according to claim 2 , wherein R is Pr.

9. The hot plastically deformed anisotropic magnet according to claim 2 , wherein an axis of easy magnetization of a R 2 Fe 14 B crystal is aligned.

10. The hot plastically deformed anisotropic magnet according to claim 2 , wherein the alloy powder is in a flake form composed of fine crystal grains.

Assignees

• Hioki Keiko
• Yabumi Takao
• Hashino Hayato
• Daido Steel Co Ltd

Inventors

• Hioki Keiko
• Yabumi Takao
• Hashino Hayato

Classifications

• B22F1/068

  Flake-like particles · CPC title

• B22F3/04

  by applying fluid pressure {, e.g. by cold isostatic pressing [CIP]} · CPC title

• B22F3/16

  in successive or repeated steps · CPC title

• C21D8/1205

  involving particular fabrication steps or treatments of ingots or slabs · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title