Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition

Qiushuang Zhang,Jiling Zeng,Xiao Yang,Renjie Chen,Aru Yan,Xuejing Cao,Shuai Guo

doi:10.1063/1.5007267

Abstract

The chemical bath deposition (CBD) method is used to diffuse the heavy rare earth element in order to obtain the high coercivity magnets with low heavy rare earth element. The jet mill powders are soaked in the alcohol suspension of Dy(CH3CHOHCH3)3 (Dy-ipa) so that Nd2Fe14B powder particles are surrounded by Dy-ipa homogeneously. By adding 1.0 wt. % Dy, the coercivity of magnet is increased from 14.47 kOe to 17.55 kOe with slight reduction of remanence after grain boundary diffusion (GBD) in the sintering and annealing processes. The temperature coefficient of coercivity optimizes from -0.629 %/°C to -0.605 %/°C as well as that of remanence improves from -0.108 %/°C to -0.100 %/°C. The CBD method is helpful for thermal stability and alignment either. The relation between the microstructure and the coercivity has been studied systematically.

Highlights

Nd-Fe-B magnets with remarkable properties have widespread application, especially in the field of hybrid electric vehicles and wind turbines.[1]
It can be seen that the Dy atoms were coated uniformly on the surface of magnetic powders, avoiding agglomerate phase appearing in grain boundary, which benefits to the increasement of coercivity.[7]
By applying the chemical bath deposition (CBD) method, the diffused magnets maintain good squareness, which attributes to the Dy atoms are primarily spread in the Nd-rich phase of the whole magnet

Summary

Introduction

Nd-Fe-B magnets with remarkable properties have widespread application, especially in the field of hybrid electric vehicles and wind turbines.[1]. Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition An approach to obtain high coercivity of the sintered Nd-Fe-B magnets with less addition of heavy rare earth is very necessary.

Results

Conclusion