RFeB-BASED MAGNET PRODUCTION METHOD AND RFeB-BASED SINTERED MAGNETS

Title:

RFeB-BASED MAGNET PRODUCTION METHOD AND RFeB-BASED SINTERED MAGNETS

Document Type and Number:

WIPO Patent Application WO/2014/148356

Kind Code:

A1

Abstract:

The present invention addresses the problem of providing a production method for RFeB-based sintered magnets having high magnetic properties, manufactured using a grain boundary diffusion method, said RFeB-based sintered magnets having excellent corrosion resistance and little energy loss. A paste (12) is applied to the surfaces of an RFeB-based sinter (11) comprising crystal grains having a main phase of R2Fe14B, which contains a light rare earth element (RL) comprising neodymium and/or praseodymium as a main rare earth element (R). The paste (12) is obtained by mixing a metal powder containing a heavy rare-earth element (RH) comprising at least one of dysprosium, holmium and terbium, with an organic material having an oxygen atom in the molecular structure. A grain boundary diffusion process is then conducted by heating the paste (12) while being brought into contact with the surfaces. A protective layer (13) containing an oxide of the light rare earth element (RL) is thus formed on the surfaces. The protective layer (13) has excellent corrosion resistance and has high electrical resistivity, and therefore suppresses the occurrence of eddy currents during use, contributing to a reduction in energy loss.

Inventors:

SAGAWA MASATO (JP)
TAKAGI SHINOBU (JP)

Application Number:

PCT/JP2014/056705

Publication Date:

September 25, 2014

Filing Date:

March 13, 2014

Export Citation:

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Assignee:

INTERMETALLICS CO LTD (JP)
DAIDO STEEL CO LTD (JP)

International Classes:

H01F41/02; B22F1/10; B22F3/24; B22F9/00; C22C38/00; H01F1/057; H01F1/08

Domestic Patent References:

WO2011122667A1	2011-10-06
WO2008032426A1	2008-03-20

Foreign References:

JP2007258455A	2007-10-04
JPH06244011A	1994-09-02

Other References: