Effect of multicomponent Tb-Cu films diffusion on the magnetic properties and thermal stability of sintered Nd-Fe-B magnets

In order to improve the diffusion characteristics of heavy rare earth in the grain boundary, effects of the diffusion process as well as the ratio of Tb and Cu (RTb/Cu) during the layered deposition process on the magnetic properties of Tb-Cu diffused Nd-Fe-B magnets were systematically investigated. The coercivity of the diffused magnet with RTb/Cu = 4:1 was enhanced most, which increased from 10.86 kOe to 21.80 kOe. Cu greatly improved the composition homogenization of diffused magnets. For the present designed diffused magnet, the highest utilization efficiency of Tb reached 43.96 kOe/wt%. Moreover, the reduced demagne-tization risk of sintered Nd-Fe-B magnets was verified by using finite element method based on the ex-perimentally obtained temperature characteristics of the magnet.(c) 2023 Elsevier B.V. All rights reserved.