Method of manufacturing alloy for r-t-b-based rare earth sintered magnet and method of manufacturing r-t-b-based rare earth sintered magnet

Patent metadata

Field	Value
Publication number	US-2016012946-A1
Application number	US-201514789495-A
Country	US
Kind code	A1
Filing date	Jul 1, 2015
Priority date	Jul 8, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

Provided is a method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet, with which an R-T-B-based magnet having high coercive force can be obtained even when the B concentration is low and the Dy concentration is zero or extremely low.
This method includes: a casting step of manufacturing a cast alloy by casting a molten alloy, a hydrogenating step of absorbing hydrogen in the cast alloy; and a dehydrogenating step of removing hydrogen from the cast alloy absorbing hydrogen in an inert gas atmosphere at a temperature lower than 550° C., wherein the molten alloy consists of B, a rare earth element R, a transition metal T essentially containing Fe, a metal element M, and unavoidable impurities, in which the R content is 13 at % to 15.5 at %, the B content is 5.0 at % to 6.0 at %, the M content is 0.1 at % to 2.4 at %, the T content is a balance, a ratio of a Dy content to the total content of the rare earth element is 0 at % to 65 at %, and the molten alloy satisfies the below formula (1).
0.32≦B/TRE≦0.40  (1).

First claim

What is claimed is:

1 . A method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet, comprising:
a casting step of manufacturing a cast alloy by casting a molten alloy, a hydrogenating step of absorbing hydrogen in the cast alloy; and a dehydrogenating step of removing hydrogen from the cast alloy that absorbs hydrogen in an inert gas atmosphere at a temperature lower than 550° C., wherein the molten alloy comprises B; a rare earth element R; a transition metal T comprising Fe; a metal element M that comprises at least one metal selected from the group consisting of Al, Ga, and Cu; and unavoidable impurities, the R content is 13 at % to 15.5 at %, the B content is 5.0 at % to 6.0 at %, the M content is 0.1 at % to 2.4 at %, the T content is a balance, a ratio of a Dy content to a total content of the rare earth element is 0 at % to 65 at %, and the molten alloy satisfies the below formula (1):
0.32≦B/TRE≦0.40  (1)

wherein B represents a boron concentration (at %), and TRE represents a total concentration (at %) of all the rare earth elements in the formula (1).

2 . A method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet, comprising:
a casting step of manufacturing a cast alloy by casting a molten alloy, a hydrogenating step of absorbing hydrogen in the cast alloy; and a dehydrogenating step of removing hydrogen from the cast alloy that absorbs hydrogen in a vacuum at a temperature lower than 600° C., wherein the molten alloy comprises B; a rare earth element R; a transition metal T comprises Fe; a metal element M that comprises at least one metal selected from the group consisting of Al, Ga, and Cu; and unavoidable impurities, the R content is 13 at % to 15.5 at %, the B content is 5.0 at % to 6.0 at %, the M content is 0.1 at % to 2.4 at %, the T content is a balance, a ratio of a Dy content to a total amount of the rare earth element is 0 at % to 65 at %, and the molten alloy satisfies the below formula (1):
0.32≦B/TRE≦0.40  (1)

wherein B represents a boron concentration (at %), and TRE represents a total concentration (at %) of all the rare earth elements in the formula (1).

3 . The method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 1 ,
wherein the dehydrogenating step is performed at 300° C. to 500° C.

4 . The method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 2 ,
wherein the dehydrogenating step is performed at 300° C. to 500° C.

5 . A method of manufacturing an R-T-B-based rare earth sintered magnet,
wherein an alloy for an R-T-B-based rare earth sintered magnet, which is manufactured by using the method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 1 , is used.

6 . A method of manufacturing an R-T-B-based rare earth sintered magnet,
wherein an alloy for an R-T-B-based rare earth sintered magnet, which is manufactured by using the method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 2 , is used.

7 . A method of manufacturing an R-T-B-based rare earth sintered magnet,
wherein an alloy for an R-T-B-based rare earth sintered magnet, which is manufactured by using the method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 3 , is used.

8 . A method of manufacturing an R-T-B-based rare earth sintered magnet,
wherein an alloy for an R-T-B-based rare earth sintered magnet, which is manufactured by using the method of manufacturing an alloy for an R-T-B-based rare earth sintered magnet according to claim 4 , is used.

9 . A method of manufacturing an R-T-B-based rare earth sintered magnet, comprising steps of
manufacturing an alloy for an R-T-B-based rare earth sintered magnet by using the method according to claim 1 , and manufacturing an R-T-B-based rare earth sintered magnet by using the obtained alloy for an R-T-B-based rare earth sintered magnet.

10 . A method of manufacturing an R-T-B-based rare earth sintered magnet, comprising steps of
manufacturing an alloy for an R-T-B-based rare earth sintered magnet by using the method according to claim 2 , and manufacturing an R-T-B-based rare earth sintered magnet by using the obtained alloy for an R-T-B-based rare earth sintered magnet.

11 . The method of manufacturing an R-T-B-based rare earth sintered magnet according to claim 9 ,
wherein in the step of manufacturing an alloy for an R-T-B-based rare earth sintered magnet, the dehydrogenating step is performed at 300° C. to 500° C.

12 . The method of manufacturing an R-T-B-based rare earth sintered magnet according to claim 10 ,
wherein in the step of manufacturing an alloy for an R-T-B-based rare earth sintered magnet, the dehydrogenating step is performed at 300° C. to 500° C.

Assignees

• Showa Denko Kk

Inventors

• Horikita Masaki
• Yamazaki Takashi
• Nakajima Kenichiro

Classifications

• B22F9/023

  Hydrogen absorption · CPC title

• H01F1/0573 Primary

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

• H01F1/0577

  sintered · CPC title

• H01F41/0266

  Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11) · CPC title

• B22F9/08

  by casting, e.g. through sieves or in water, by atomising or spraying (using electric discharge B22F9/14) · CPC title