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Title:
METHOD FOR PRODUCING R-T-B SYSTEM SINTERED MAGNET
Document Type and Number:
WIPO Patent Application WO/2012/105399
Kind Code:
A1
Abstract:
Provided is a method for producing an R-T-B system sintered magnet, wherein a recovery step in a coarse grinding step (A) is carried out in a recovery chamber (40) which is provided with an inert gas introduction means (42), a vacuum evacuation means (43), a carry-in port, a discharge port (40a) that is arranged at a lower part of the recovery chamber (40), and a recovery container (60). The recovery step comprises: a carry-in step wherein a process container (50) is carried into the recovery chamber (40) from a process chamber through the carry-in port; a discharge step wherein a coarsely ground powder within the process container (50) is discharged into the recovery chamber (40) after reducing the pressure within the recovery chamber (40); a gas introduction step wherein an inert gas is introduced into the recovery chamber (40) by the inert gas introduction means (42); and an alloy recovery step wherein the coarsely ground powder is recovered in the recovery container (60) through the discharge port (40a). Addition of a grinding assistant in a mixing step is carried out in the alloy recovery step in the recovery step after a cooling step, so that the coarsely ground powder remaining in the recovery chamber after hydrogen pulverization is reduced. Consequently, the amount of oxygen contained in an R-T-B system sintered magnet is reduced, thereby improving the magnet characteristics.

Inventors:
MOCHIZUKI MITSUAKI (JP)
NAKAYAMA SHOJI (JP)
SONODA KAZUHIRO (JP)
Application Number:
PCT/JP2012/051620
Publication Date:
August 09, 2012
Filing Date:
January 26, 2012
Export Citation:
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Assignee:
HITACHI METALS LTD (JP)
MOCHIZUKI MITSUAKI (JP)
NAKAYAMA SHOJI (JP)
SONODA KAZUHIRO (JP)
International Classes:
C22C33/02; B02C19/06; B02C19/18; B02C21/00; B22F1/00; B22F3/00; B22F3/02; B22F9/04; H01F1/053; H01F1/08; H01F41/02; C22C38/00
Domestic Patent References:
WO2011013489A12011-02-03
Foreign References:
JP2005118625A2005-05-12
JP2006286859A2006-10-19
JP2011214044A2011-10-27
JP2731337B21998-03-25
JP3418605B22003-06-23
JP2005118625A2005-05-12
Other References:
See also references of EP 2671958A4
Attorney, Agent or Firm:
TSUJITA Takashi et al. (JP)
Yukifumi Tsujita (JP)
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Claims: