Coercivity enhancement of Nd-Fe-B sintered magnet by grain boundary diffusion process using Pr-Tb-Cu-Al alloys

Lu, Kening; Bao, Xiaoqian; Chen, Guixian; Mu, Xing; Zhang, Xuejiao; Lv, X. K.; Ding, Yong; Gao, Xuexu

doi:10.1016/j.jmmm.2019.01.062

Cited by 30 publications

(4 citation statements)

References 34 publications

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“…According to earlier reports, bcc-Nd 2 O 3 and fcc-Nd oxides occasionally coexist in Nd-rich phases. 18,25,28 The bcc-(Ce, Nd) 2 O 3 phase is considered to be metastable and forms only for a narrow range of O content. 11 As shown in Fig.…”

Section: Articlementioning

confidence: 99%

Crystallographic studies of the intergranular phases in sintered PrNd23Ce7Gd1.5FebalB0.93Cu0.35M1 magnet with commercial N40M magnetic properties

Huang

Mao

Wang³

et al. 2023

AIP Advances

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In this work, we focus on the modification of the Cu element in commercial N40M magnets toward the composition and structure of the grain boundary phase. The magnetic properties and microstructure of Ce-magnets with low and high Cu content were investigated. The Ce-magnet with high Cu-content has higher coercivity and a more continuous and homogenous grain boundary phase. The grain boundary phase’s structural shift is found to be the source of the coercivity change. The transmission electron microscopy study shows that the PrNd23Ce7Gd1.5FebalB0.93Cu0.35M1 magnet contains fcc and hcp type (Ce, Nd)-oxide phases, each with a different O concentration. The formation of the superlattice has been examined, and the superlattice spots show that the Cu-rich phases have an ordered structure.

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Section: Articlementioning

confidence: 99%

Crystallographic studies of the intergranular phases in sintered PrNd23Ce7Gd1.5FebalB0.93Cu0.35M1 magnet with commercial N40M magnetic properties

Huang

Mao

Wang³

et al. 2023

AIP Advances

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“…The metallic Nd phase can exist with fcc and double hcp (hP4) lattice. The oxide particles in Nd 2 Fe 14 B grains TJs are clearly visible in SEM [5, 6,13,14,16 -19, 35 -37] and TEM [6,7,14,17,27,28,38,39]. In addition to the results obtained from XRD and electron diffraction, the EDS measurements also reveal the presence of oxygen in these non-metallic particles [7,15,16, 20, 35 -37, 40].…”

Section: Gb Oxides In Nd-fe-b-based Alloysmentioning

confidence: 99%

Grain boundaries in Nd-Fe-B-based alloys

et al. 2020

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In this review we consider the microstructure of grain boundaries (GBs) in the Nd-Fe-B-based alloys for permanent magnets. It is generally accepted that the unique hard magnetic properties of such alloys are controlled by the thin layers of a Nd-rich phase in Nd 2 Fe 14 B / Nd 2 Fe 14 B GBs. These GB layers ensure the magnetic isolation of Nd 2 Fe 14 B grains from each other. It is generally supposed that such GB layers contain metallic Nd or Nd-rich intermetallic compounds. However, the commercial Nd-Fe-B-based permanent magnets frequently contain the tangible amount of neodymium oxide Nd 2 O 3 in the triple junctions between Nd 2 Fe 14 B grains. In this review we show that oxide layers are also present in the GBs in Nd-Fe-B-based permanent magnets. The Nd-based phase in GBs can form continous layers between Nd 2 Fe 14 B grains (this case is called complete wetting). It corresponds to the zero contact angle between GB and Nd-rich phase. If the contact angle is non-zero, the Nd-based phase forms the chain of particles in the GB. In turn, if the GB between these particles is "dry", this case is called the incomplete wetting. If the GB between the Nd-rich particles contains the thin layer of a Nd-rich phase (either metallic or oxide), this case is called the pseudo-incomplete (or pseudo-partial) GB wetting.

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“…5–8 The grain boundary diffusion (GBD) technique is a promising approach to enhance the coercivity with low consumption of HREs and tiny reduction of remanence, which has been industrialized for many years. 9–13 Up to now, much work 14–16 has focused on optimizing the diffusion source to obtain high diffusion efficiency in HREs. Various types of diffusion sources, such as inorganic compounds, 17,18 metals, 19 and alloys 20 have been developed.…”

Section: Introductionmentioning

confidence: 99%

Tb–Cu grain boundary diffusion effects on single- and multi-main-phase Nd–Fe–B based magnets

Liu

et al. 2023

J. Mater. Chem. C

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Coercivity enhancement of Nd-Fe-B sintered magnet by grain boundary diffusion process using Pr-Tb-Cu-Al alloys

Cited by 30 publications

References 34 publications

Crystallographic studies of the intergranular phases in sintered PrNd23Ce7Gd1.5FebalB0.93Cu0.35M1 magnet with commercial N40M magnetic properties

Crystallographic studies of the intergranular phases in sintered PrNd23Ce7Gd1.5FebalB0.93Cu0.35M1 magnet with commercial N40M magnetic properties

Grain boundaries in Nd-Fe-B-based alloys

Tb–Cu grain boundary diffusion effects on single- and multi-main-phase Nd–Fe–B based magnets

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