Influence of Additional Micro-Sized Particles of Dy-Nd-Cu-Al on Magnetic Properties of Sintered Nd-Fe-B Magnets

Pham Thi Thanh; Dinh Thi Kim Oanh; Nguyen Hai Yen; Nguyen Huy Dan

doi:10.1166/jnn.2021.19100

Influence of Additional Micro-Sized Particles of Dy-Nd-Cu-Al on Magnetic Properties of Sintered Nd-Fe-B Magnets

J Nanosci Nanotechnol. 2021 Apr 1;21(4):2558-2562. doi: 10.1166/jnn.2021.19100.

Authors

Pham Thi Thanh¹, Dinh Thi Kim Oanh², Nguyen Hai Yen¹, Nguyen Huy Dan¹

Affiliations

¹ Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Ha Noi, 100000, Viet Nam.
² Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Ha Noi, 100000, Viet Nam.

PMID: 33500075
DOI: 10.1166/jnn.2021.19100

Abstract

In this work, we investigated the influence of concentration of the additional micro-sized particles of Dy₄₀Nd₃₀Al₃₀ and Nd₄₀Cu₃₀Al₃₀ on magnetic properties of the sintered Nd_16.5Fe₇₇B_6.5 magnets. The additional particles with size in the range of 1-3 μm were prepared by ball milling method and then mixed into micrometer Nd_16.5Fe₇₇B_6.5 master powder with different weight fractions before magnetic anisotropic pressing, vacuum sintering and annealing. The results show that the coercivity of the sintered Nd-Fe-B magnets can be improved considerably by introducing additional particles to the grain boundaries. The improvement of the coercivity Hc of the magnets is clearly dependent on the composition and concentration of the additional microparticles. The Hc increases linearly from 8.5 kOe to 17 kOe with increasing the weight fraction of the Dy₄₀Nd₃₀Al₃₀ microparticles from 0 to 5%. Meanwhile, the coercivity of the magnet reaches a maximum value of 11.7 kOe with 4 wt% addition of Nd₄₀Cu₃₀Al₃₀. The quite high maximum energy products, (BH)_max > ₃₀ MGOe, were also obtained for the magnets added with the microparticles. The obtained hard magnetic parameters of the magnets can be applied in practice.