Influences of element segregation on the magnetic properties in nanocrystalline Nd-Ce-Fe-B alloys

Zhao, Lizhong; Li, Chengli; Zhang, Hao; Liu, Xiaolian; Liao, Xuefeng; Zhang, Jiasheng; Su, Kunpeng; Li, Lingwei; Yu, Hongya; Grenèche, Jean‐Marc; Jin, Jiaying; Liu, Zhongwu

doi:10.1016/j.matchar.2018.12.022

Cited by 40 publications

(16 citation statements)

References 19 publications

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“…In recent years, the low cost of Ce-containing Nd-Fe-B permanent magnets, in some areas being a potential alternative to those based on expensive rare-earth elements (Nd, Pr, Dy, Tb), has stimulated considerable research efforts [1,2]. [4,7] The anisotropy of the Nd 2 Fe 14 B compound is dominated by the rare-earth atoms that occupy two inequivalent sites, 4f and 4g, of the tetragonal structure [8,9].…”

Section: Introductionmentioning

confidence: 99%

Simulating the Hysteretic Characteristics of Hard Magnetic Materials Based on Nd2Fe14B and Ce2Fe14B Intermetallics

et al. 2020

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The Ce2Fe14B intermetallic, like Nd2Fe14B, has the tetragonal Nd2Fe14B-type structure (space group P42/mnm), in which Ce ions have a mixed-valence state characterized by the coexistence of trivalent 4f1 and tetravalent 4f0 electron states. Despite the fact that the saturation magnetization, magnetic anisotropy field, and Curie temperature of the Ce2Fe14B intermetallic are substantially lower than those of Nd2Fe14B and Pr2Fe14B, Ce2Fe14B retains the capacity of being able to be used in the manufacturing of rare-earth permanent magnets. Moreover, at low temperatures, the anisotropy field of Се2Fe14B is higher than that of Nd2Fe14B, and Се2Fe14B does not undergo the spin-reorientation transition. In this respect, studies of (Nd, Ce)-Fe-B alloys, which are intended for the improvement of the service characteristics-to-cost ratio, are very relevant. A model and algorithm for calculating the hysteresis loops of uniaxial hard magnetic materials with allowance for the K1 and K2 (K2 > 0 and K1 > 0 and K1 < 0) magnetic anisotropy constants were developed and allowed us to obtain data on their effect on the parameters of hysteresis loops for a wide temperature range (0–300 K). The simulation and analysis of hysteresis loops of the quasi-ternary intermetallics (Nd1−хСех)2Fe14B (х = 0–1) was performed. Results of the simulation indicate that the alloying of the Nd2Fe14B intermetallic with Ce to x = 0.94 (1) does not completely eliminate the negative effect of spin-reorientation phase transition on the residual magnetization of the (Nd1−хCeх)2Fe14B intermetallic and (2) slightly decreases the slope of magnetization reversal curve.

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Section: Introductionmentioning

confidence: 99%

Simulating the Hysteretic Characteristics of Hard Magnetic Materials Based on Nd2Fe14B and Ce2Fe14B Intermetallics

et al. 2020

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“…The Mössbauer spectrometry results showed that the ThMn 12 -type structure obtained after arc-melting was clearly not homogeneous. As it was not possible to describe three subspectra for 8i, 8j and 8f positions ( Figure 3 ), a distribution of parameters was used by similarity to these already known from previous investigations, where Ce substitution for Nd in similar alloys was reported to be responsible for lowering of the hyperfine field ( B hf ) [ 39 , 40 , 41 ]. Consequently, the mean value of the hyperfine field parameter was checked and estimated to be equal to 28.7 ± 0.5, 28.7 ± 0.5, 29.9 ± 0.5 and 30.6 ± 0.5 T for the Zr 0.4 Ce 0.6 Fe 10 Si 2 , Zr 0.3 Nd 0.1 Ce 0.6 Fe 10 Si 2 , Zr 0.2 Nd 0.2 Ce 0.6 Fe 10 Si 2 , and Zr 0.1 Nd 0.3 Ce 0.6 Fe 10 Si 2 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Influence of Nd Substitution on the Phase Constitution in (Zr,Ce)Fe10Si2 Alloys with the ThMn12 Structure

et al. 2023

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Iron-based compounds with a ThMn12-type structure have the potential to bridge the gap between ferrites and high performance Nd2Fe14B magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 wt.% less rare earth elements in comparison with the 2:14:1 phase. On the other hand, the main issue delaying the development of Fe-rich alloys with a ThMn12-type structure is their structural stability. Therefore, various synthesis methods and stabilizing elements have been proposed to stabilize the structure. In this work, the influence of increasing Nd substitution on the phase constitution of Zr0.4−xNdxCe0.6Fe10Si2 (0 ≤ x ≤ 0.3) alloys was analyzed. X-ray diffraction and 57Fe Mössbauer spectrometry were used as the main methods to derive the stability range and destabilization routes of the 1:12 structure. For the arc-melted samples, an increase in the lattice parameters of the ThMn12-type structure was observed with the simultaneous growth of bcc-(Fe,Si) content with increasing Nd substitution. After isothermal annealing, the ThMn12-type structure (and the coexisting bcc-(Fe,Si)) were stable over the whole composition range. While the formation of a 1:12 phase was totally suppressed in the as-cast state for x = 0.3, further heat treatment resulted in the growth of about 45% of the ThMn12-type phase. The results confirmed that the stability range of ThMn12-type structure in the Nd-containing alloys was well improved by other substitutions and the heat treatment, which in turn, is also needed to homogenize the ThMn12-type phase. After further characterization of the magnetic properties and optimization of microstructure, such hard/soft magnetic composites can show their potential by exploiting the exchange spring mechanism.

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“…With the constant consumption of expensive Pr, Nd, Dy, and Tb REs, the highly abundant REs (HAREs) of Ce and La face a large backlog due to the weak intrinsic magnetic properties of the compounds of (Ce/La) 2 Fe 14 B, [ 25,26 ] resulting in a serious imbalance in RE utilization. [ 27–30 ] They have been used in low‐cost RE‐Fe–B magnets, for example, multiple main‐phase magnets; [ 31–33 ] however, less attention focuses on using them for diffusion sources. Our previous work tried to exploit La and La/Ce‐based low‐melting sources, but their caused coercivity enhancement is still very margin.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Role of Element Grain Boundary Diffusion Mechanism in Nd–Fe–B Magnets

Zhao

et al. 2021

Adv Funct Materials

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Grain boundary diffusion (GBD) of multiple rare earths has proven effective in enhancing the performance of permanent magnets, whereas the diffusion behaviors are still unclear due to their intricate interactions. In this work, the synergistic effects of three rare earths (Tb, Ce, and La) on the grain boundaries diffusion process are investigated, achieving a high‐performance diffused Nd–Fe–B magnet with the high coercivity of 1822 kA m−1 and thermal stability of −0.447% K−1. This promotion originates from the improved diffusion depth of Tb at specific regions, induced by the coordination effects of Ce and La, as evidenced via electron probe microanalysis and the first‐principles calculations. It thus results in the uniform formation of Tb‐diffused magnetic harden grains, associated with the strongly pinned domain walls, which is further observed directly by in situ Lorentz transmission electron microscopy and reconstructed by micromagnetic simulations. The study provides insight into the role of element GBD mechanism and has promising potential to explore other element systems as diffusion sources for permanent magnets.

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Influences of element segregation on the magnetic properties in nanocrystalline Nd-Ce-Fe-B alloys

Cited by 40 publications

References 19 publications

Simulating the Hysteretic Characteristics of Hard Magnetic Materials Based on Nd2Fe14B and Ce2Fe14B Intermetallics

Simulating the Hysteretic Characteristics of Hard Magnetic Materials Based on Nd2Fe14B and Ce2Fe14B Intermetallics

Influence of Nd Substitution on the Phase Constitution in (Zr,Ce)Fe10Si2 Alloys with the ThMn12 Structure

Understanding the Role of Element Grain Boundary Diffusion Mechanism in Nd–Fe–B Magnets

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