Title:
Method for manufacturing sintered Nd-Fe-B magnetic material that does not contain heavy rare earth elements
Document Type and Number:
Japanese Patent JP6366666
Kind Code:
B2
Abstract:
The present invention relates to sintered Nd-Fe-B magnets, which are free of any heavy rare earth elements. The present invention further relates to corresponding manufacturing process thereof. The process comprises the steps of:
a) providing an alloy sheet made of a Nd-Fe-B magnet composition, wherein Pr and Nd are present in a combined amount of 31 wt.% ¤ Pr and Nd ¤ 34wt.%; B is present in an amount of 0.8 wt.% ¤ B ¤ 1.2 wt%; Al is present in an amount of 0.4 wt.% ¤ Al ¤ 0.8 wt.%; Co is present in an amount of 0.6 wt.% ¤ Co ¤ 1.2 wt.%; Cu is present in an amount of 0.2 wt.% ¤ Cu ¤ 0.5 wt.%; Ga is present in an amount of 0.1 wt.% ¤ Ga ¤ 0.4 wt.%; and wherein the balance element is Fe;
b) the alloy sheet is broken into alloy pieces by a decrepitation process;
c) an amount of 0.05 to 0.5 wt.% lubricant is added to the alloy powder and then the mixture is milled by a jet mill process until an average particle size D50 of the resulting alloy powder ranges from 2.0 µm to 3.0 µm;
d) another amount of 0.03 to 0.2 wt.% lubricant is added to the alloy powder after milling and mixed, then the alloy powder is compressed into compacts while applying an orienting magnetic field of 2.0 to 2.5T; and
e) the compacts are sintered in a vacuum furnace, wherein a pressure within the furnace during the sintering step is equal to or less than 5x10 -2 Pa.
Inventors:
Ding
Peng
Royal sea
Chen Shurai
Peng
Royal sea
Chen Shurai
Application Number:
JP2016214850A
Publication Date:
August 01, 2018
Filing Date:
November 02, 2016
Export Citation:
Assignee:
Yantai Steel Magnetic Materials Stock Co., Ltd.
International Classes:
B22F3/00; B22F1/10; B22F3/24; B22F9/04; C22C33/02; C22C38/00; H01F1/057; H01F41/02
Domestic Patent References:
| JP2007134353A |
Foreign References:
| WO2015147053A1 | ||||
| WO2013054842A1 | ||||
| CN104143403A |
Attorney, Agent or Firm:
Kenji Hidaka