Method for manufacturing rare-earth magnets

Patent metadata

Field	Value
Publication number	US-10002695-B2
Application number	US-201514829807-A
Country	US
Kind code	B2
Filing date	Aug 19, 2015
Priority date	Oct 3, 2014
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

Provided is a method for manufacturing a rare-earth magnet having good workability and capable of manufacturing a rare-earth magnet having low oxygen density. A method for manufacturing a rare-earth magnet includes: a first step of applying or spraying graphite-based lubricant GF on an inner face of a forming die M, and charging magnetic powder MF as a rare-earth magnet material in the forming die M, followed by cold forming, to form a cold-forming compact 10 having a surface on which a graphite-based lubricant coat 12 is formed; a second step of performing hot forming to the cold-forming compact 10 to form a sintered body 20 having a surface on which a graphite-based lubricant coat 22 is formed; and a third step of, in order to give the sintered body 20 anisotropy, performing hot deformation processing to the sintered body 20 to form the rare-earth magnet 30.

First claim

What is claimed is:

1. A method for manufacturing a rare-earth magnet, comprising:
a first step of applying or spraying graphite-based lubricant on an inner face of a forming die, and charging magnetic powder as a rare-earth magnet material in the forming die, followed by cold forming, to form a cold-forming compact having a surface on which a graphite-based lubricant coat is formed;
a second step of placing the cold-forming compact in a cavity of a die containing air and performing hot forming to the cold-forming compact to form a sintered body having a surface on which the graphite-based lubricant coat is formed; and
a third step of, in order to give the sintered body anisotropy, performing hot deformation processing to the sintered body to form the rare-earth magnet.

Assignees

• Toyota Motor Co Ltd

Inventors

• Haga Kazuaki
• Inuzuka Tomonori
• Ikeda Yuya

Classifications

• B22F2003/026

  Mold wall lubrication or article surface lubrication · CPC title

• B22F3/10

  Sintering only · CPC title

• B22F2003/175

  by hot forging, below sintering temperature · CPC title

• B22F2009/048

  by pulverising a quenched ribbon · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title