Production and corrosion resistance of NdFeBZr magnets with an improved response to thermal variations during sintering

Yu, Lian; Zhong, X.L.; Zhang, Y.P.; Yan, Y.; Zhen, Yuhua; Zakotnik, M.

doi:10.1016/j.jmmm.2010.12.029

Cited by 17 publications

(4 citation statements)

References 9 publications

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“…Magnetic performance of the (Nd, Dy) 12.99 Fe bal B 5.9 magnet prepared by the conventional single alloy approach is (BH) max = 34.5 MGOe, B r = 1.40 T, H cj = 6.6 kOe. [76] Even blended with 1 at.% Dy (melting point of 1412 • C), the magnetic performance of a Nd 13 Fe bal CoNbB 7 magnet can only be slightly improved to H cj = 7.2 kOe, (BH) max = 24.5 MGOe, and B r = 1.11 T. [77] It indicates that if the melting point of aiding alloys is much higher than the sintering temperature (1030-1100 • C), the magnetic performance cannot be improved via the binary-alloy approach. The introduction of low-melting-point Dy 71.5 Fe 28.5 aiding alloy not only leads to good densification but also forms a magnetic hardening (Nd, Dy) 2 Fe 14 B shell surrounding the 2:14:1 phase grains, thus making it obtainable of reduced TRE content and improved magnetic performance simultaneously.…”

Section: Design Guidelines For Grain Boundary Restructuringmentioning

confidence: 99%

Grain boundary restructuring and La/Ce/Y application in Nd–Fe–B magnets*

Yan

Jin

2019

Chinese Phys. B

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Since the 1980s, Nd–Fe–B with largest energy product (BH)max approaching the theoretical limit has become the landmark of permanent magnetic material. The application spectrum for Nd–Fe–B continues to expand over time both in the industrial and commercial sectors, which leads to growing research interests for solving the long-standing drawbacks of Nd–Fe–B, i.e., poor corrosion resistance, low coercivity, high Dy/Tb and low La/Ce/Y consumption. Concerning the above obstacles, we aim to present the novel grain boundary restructuring (GBR) approach, from GB design, processing, to structure evolution and property evaluation with a focus on the corrosion and coercivity mechanism of the restructured 2:14:1-typed magnets. Starting with an introduction to the fundamental of GBR, two representative examples, high-electrode-potential (Pr, Nd)32.5Fe62.0Cu5.5 and low-melting-point Dy71.5Fe28.5, are given with detailed descriptions of the advantages of GBR to enhance the intrinsic anti-corrosion stability and to strengthen the coercivity at low Dy consumption. Microstructure–property correlations are established to understand the critical importance of regulating the restructured GB phase to maximize the all-round performance of the 2:14:1-typed permanent magnets. Aiming at sustainable and balanced development of rare earth (RE) industry, the proceeding section proposes new prototypes of La–Ce and Y–Ce co-substitutions with dual benefits of stabilizing the 2:14:1 tetragonal phase and strengthening the intrinsic hard magnetism. The findings of additional REFe2 intergranular phase delight that the GBR approach also opens up a new horizon of research and application to develop high-performance La/Ce/Y-rich permanent magnets with deliberately tailored GB phase.

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Section: Design Guidelines For Grain Boundary Restructuringmentioning

confidence: 99%

Grain boundary restructuring and La/Ce/Y application in Nd–Fe–B magnets*

Yan

Jin

2019

Chinese Phys. B

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“…However, such borides, under the form of nanoprecipitates, are liable to limit the grain growth during sintering. This pinning effect allows the sintering temperature to be adjusted in order to obtain full densification and better magnetic properties [147], [148]. Ta, Nb and Mo are also mentioned to help the microstructure refinement in (Ce,Nd)-Fe-B alloys [149], [150].…”

Section: Zr and Hf Additionmentioning

confidence: 99%

Nd2Fe14B permanent magnets substituted with non-critical light rare earth elements (Ce, La): A review

Delette

2023

Journal of Magnetism and Magnetic Materials

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“…Their demand and subsequently their production has considerably increased [1][2][3][4]. The markedly growing use of NdFeB magnets has induced the correspondingly increasing generation of scrap materials, because about 25% of the input amount is discharged as waste scrap during the manufacturing process [5].…”

Section: Introductionmentioning

confidence: 99%

Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment

Chung

Kim

Yoon

2015

Archives of Metallurgy and Materials

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The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100• C was performed. The resultant powders were then leached in 0.5M H 2 SO 4 solution at 25• C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.

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Production and corrosion resistance of NdFeBZr magnets with an improved response to thermal variations during sintering

Cited by 17 publications

References 9 publications

Grain boundary restructuring and La/Ce/Y application in Nd–Fe–B magnets*

Grain boundary restructuring and La/Ce/Y application in Nd–Fe–B magnets*

Nd2Fe14B permanent magnets substituted with non-critical light rare earth elements (Ce, La): A review

Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment

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