Reduction in Heavy Rare Earth Diffusion Sources in Sintered Nd-Fe-B Magnets via Grain Boundary Diffusion of Dy70Ce70-xCu30

Dongbiao Yang; Xiao Gao; Shuwei Zhong; Honglong Yang; Farao Zhang

doi:10.3390/ma17235784

Reduction in Heavy Rare Earth Diffusion Sources in Sintered Nd-Fe-B Magnets via Grain Boundary Diffusion of Dy₇₀Ce_70-xCu₃₀

Materials (Basel). 2024 Nov 26;17(23):5784. doi: 10.3390/ma17235784.

Authors

Dongbiao Yang^{1

2}, Xiao Gao^{1

3}, Shuwei Zhong^{1

3}, Honglong Yang^{1

3}, Farao Zhang¹

Affiliations

¹ Jiangxi Provincial Key Laboratory of Magnetic Metallic Materials and Devices, College of Rare Earths, Jiangxi University of Science and Technology, Ganzhou 341000, China.
² Beilun Customs People's Republic of China, Ningbo 315800, China.
³ National Rare Earth Functional Materials Innovation Center, Ganzhou 341000, China.

PMID: 39685220
DOI: 10.3390/ma17235784

Abstract

This study investigates the effect of Ce on the diffusion behavior of Dy-Cu alloys. The addition of Ce reduces the diffusion source melting point and promotes the formation of low-melting alloy phases, benefiting the diffusion behavior. The diffusion source with 10 wt.% of Ce shows the best magnetic performance, the coercivity of the magnet increases from 18.47 kOe to 23.60 kOe, and the incremental coercivity reaches 5.13 kOe. Ce diffusion improves the utilization of Dy, enhances diffusion uniformity, and promotes coercivity improvement. Ce also optimizes and regulates grain boundary phase structure distribution, consistent with magnetic property changes. Dy₇₀Cu₃₀ with an excessive thick shell layer wastes Dy and reduces utilization, while Dy₆₀Ce₁₀Cu₃₀ has a relatively thin and uniform shell layer. Ce mainly distributes in the intergranular phase region, promoting Dy diffusion from the intergranular phase to form a shell layer. Excessive Ce can distort the magnet's crystal structure, hindering magnetic property improvement. This study provides insights into optimizing the diffusion process and improving the Dy-Cu alloy.

Keywords: Nd-Fe-B magnets; coercivity; diffusion efficiency; permanent magnets.

Abstract

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