Global Patent Index - EP 0576282 A2

EP 0576282 A2 19931229 - A process for preparing R-Fe-B type sintered magnets employing the injection molding method.

Title (en)

A process for preparing R-Fe-B type sintered magnets employing the injection molding method.

Title (de)

Verfahren zur Herstellung von R-Fe-B-Typ Sintermagneten durch Einspritzgiessformen.

Title (fr)

Procédé de préparation d'aimants frittés du type R-Fe-B utilisant moulage pour injection.

Publication

EP 0576282 A2 19931229 (EN)

Application

EP 93304944 A 19930624

Priority

  • JP 4601093 A 19930209
  • JP 9719093 A 19930330
  • JP 12489393 A 19930428
  • JP 19172792 A 19920624
  • JP 19172892 A 19920624
  • JP 28942092 A 19921001
  • JP 28942192 A 19921001
  • JP 28942292 A 19921001

Abstract (en)

The object of the invention is to provide a manufacturing method of a complex shaped R-Fe-B type sintered anisotropic magnet improved the moldability of injection molding and preventing the reaction between R ingredients and binder and controlled the degradation of magnetic characteristics due to residual carbon and oxygen. Utilizing the R-Fe-B type alloy powder or the resin coated said alloy powder, and methylcellulose and/or agar and water, instead of the usual thermoplastic binder, it is mixed and injection molded. The molded body is dehydrated by the freeze vacuum dry method to control the reaction between R ingredients and of the R-Fe-B alloy powder and water; furthermore, by administering the de-binder treatment in the hydrogen atmosphere, and sintering it after the dehydrogen treatment, residual oxygen and carbon in the R-Fe-B sintered body is drastically reduced, improving the moldability during the injection molding to obtain a three dimensionally complex shape sintered magnet.

IPC 1-7

H01F 41/02; H01F 1/053

IPC 8 full level

B22F 3/22 (2006.01); H01F 1/057 (2006.01)

CPC (source: EP)

B22F 3/22 (2013.01); B22F 3/225 (2013.01); H01F 1/0577 (2013.01); H01F 41/0293 (2013.01); B22F 2998/00 (2013.01)

Designated contracting state (EPC)

DE FR GB NL

DOCDB simple family (publication)

EP 0576282 A2 19931229; EP 0576282 A3 19940323; EP 0576282 B1 19970924; DE 69314098 D1 19971030; DE 69314098 T2 19980312

DOCDB simple family (application)

EP 93304944 A 19930624; DE 69314098 T 19930624