US 12,131,850 B2
Rare earth magnet and preparation method thereof
Guoan Chen, Beijing (CN); Haojie Wang, Beijing (CN); Bin Fang, Beijing (CN); Fei Du, Beijing (CN); Zhan Wang, Beijing (CN); and Yugang Zhao, Beijing (CN)
Assigned to SANVAC (BEIJING) MAGNETICS CO., LTD., Beijing (CN); and BEIJING ZHONG KE SAN HUAN HI-TECH CO., LTD., Beijing (CN)
Filed by SANVAC (BEIJING) MAGNETICS CO., LTD., Beijing (CN); and BEIJING ZHONG KE SAN HUAN HI-TECH CO., LTD., Beijing (CN)
Filed on Jun. 24, 2021, as Appl. No. 17/357,073.
Application 17/357,073 is a continuation of application No. PCT/CN2018/125316, filed on Dec. 29, 2018.
Prior Publication US 2021/0335525 A1, Oct. 28, 2021
Int. Cl. H01F 1/057 (2006.01); C22C 33/02 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/10 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); H01F 41/02 (2006.01)
CPC H01F 1/0577 (2013.01) [C22C 33/02 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/06 (2013.01); C22C 38/10 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); H01F 41/0266 (2013.01); C22C 2202/02 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A NdFeB rare earth magnet comprising:
a main phase; and
a grain boundary phase including:
a white grain boundary phase including R1−T−M, wherein:
R1 represents a rare earth element containing at least one of Nd or Pr, and an atomic percentage of R1 in R1−T−M is greater than 30 at %;
T represents a component including:
at least one of Fe or Co; and
one or more unavoidable impurity elements; and
M represents a component including at least one of Al, Cu, Nb, Zr, or Sn; and
a gray grain boundary phase including Nd6Fe13Ga;
wherein:
in a microstructure observation area of the rare earth magnet:
an area of the white grain boundary phase accounts for 1-3% of a total area of the microstructure observation area; and
an area of the gray grain boundary phase accounts for 2-10% of the total area of the microstructure observation area; and
a composition of the rare earth magnet by mass percentage is as follows:
a content of R is 28-32 wt % of a total magnet weight of the rare earth magnet, R representing a component including one or more rare earth elements other than Dy and Tb, and Pr and/or Nd in R being 98-100 wt % of a total weight of R;
a content of Dy and/or Tb is 0-2 wt % of the total magnet weight;
a content of M is 0.1-1.4 wt % of the total magnet weight;
a content of Ga is 0.3-0.8 wt % of the total magnet weight;
a content of B is 0.96-1.0 wt % of the total magnet weight; and
a balance amount of T.