US 11,862,370 B2
High-resistivity sintered samarium-cobalt magnet and preparation method thereof
Nengjun Yu, Zhejiang (CN); Jianghui Sun, Zhejiang (CN); Hangfu Yang, Zhejiang (CN); Minxiang Pan, Zhejiang (CN); Qiong Wu, Zhejiang (CN); and Hongliang Ge, Zhejiang (CN)
Assigned to China Jiliang University, Hangzhou (CN)
Filed by China Jiliang University, Zhejiang (CN)
Filed on Apr. 19, 2022, as Appl. No. 17/723,646.
Claims priority of application No. 202110424362.3 (CN), filed on Apr. 20, 2021.
Prior Publication US 2022/0375662 A1, Nov. 24, 2022
Int. Cl. H01F 1/059 (2006.01); H01F 7/02 (2006.01); H01F 41/02 (2006.01); B22F 9/04 (2006.01)
CPC H01F 1/059 (2013.01) [H01F 7/02 (2013.01); H01F 41/0266 (2013.01)] 9 Claims
 
1. A method for preparing a sintered samarium-cobalt magnet, comprising the following steps:
(1) weighing fluoride, mixing the fluoride with alcohol and a surfactant, and then performing ball milling to obtain fine fluoride powder, with an average particle size of 10-200nm;
(2) rinsing and drying the fine fluoride powder prepared in step (1) in an oxygen-free glove box to obtain fluoride powder;
(3) weighing metal raw materials according to compositions of Sm2(CoFeCuZr)17 alloy, and then smelting the raw materials uniformly to obtain alloy ingots;
(4) crushing the alloy ingots, and obtaining magnetic powder by powder processing, with an average particle size of 2.5-5.2 μm;
(5) mixing the fluoride powder prepared in step (2) with alcohol, and preparing a suspension by ultrasonic treatment;
(6) spreading the magnetic powder prepared in step (4) evenly on a platinum sheet A at a bottom of a container, and pouring the suspension prepared in step (5) into the container; after pouring, placing a platinum sheet B on a surface of the liquid in a suspended manner, completely immersing the platinum sheet B in the suspension, then performing deposition treatment under an electric field, and applying a voltage to the platinum sheets A and B, with the platinum sheet B serving as a positive electrode and the platinum sheet A serving as a negative electrode, to obtain deposited magnetic powder;
(7) performing magnetic field orientation molding and cold isostatic pressing on the deposited powder prepared in step (6) to obtain compacts; and
(8) sintering, solution-treating and annealing the compacts prepared in step (7) to obtain a sintered samarium-cobalt magnet.