Variations of phase constitution and magnetic properties with Ce content in Ce-Fe-B permanent magnets

Li, Zhu-bai; Zhang, Ming; Shen, Baogen; Hu, Fengxia; Sun, J. R.

doi:10.1016/j.matlet.2016.02.149

Cited by 47 publications

(12 citation statements)

References 16 publications

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“…However, continually growing demand for Nd-Fe-B magnets and insecure supply for those closely-relied Nd/Pr/Dy/Tb due to geologic scarcity, extraction difficulties and political volatility has caused severe concerns about REs availability, which may exert spill-over effects on global economy, and security in the case of defense or military sectors26. Meanwhile, the large backlog of highly-abundant and inexpensive La/Ce (by-products of Nd/Pr/Dy/Tb during mineral extraction) due to the inferior magnetic properties of (La/Ce) 2 Fe 14 B to Nd 2 Fe 14 B111213141516171819202122 is a longstanding bottleneck for balanced utilization of RE resources41323.…”

mentioning

confidence: 99%

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

Jin

Zhang

et al. 2016

Sci Rep

127

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The global rare earth (RE) criticality, especially for those closely-relied Nd/Pr/Dy/Tb in the 2:14:1-typed permanent magnets (PMs), has triggered tremendous attempts to develop new alternatives. Prospective candidates La/Ce with high abundance, however, cannot provide an equivalent performance due to inferior magnetic properties of (La/Ce)2Fe14B to Nd2Fe14B. Here we report high figure-of-merit La/Ce-rich RE-Fe-B PMs, where La/Ce are inhomogeneously distributed among the 2:14:1 phase. The resultant exchange coupling within an individual grain and magnetostatic interactions across grains ensure much superior performance to the La/Ce homogeneously distributed magnet. Maximum energy product (BH)max of 42.2 MGOe is achieved even with 36 wt. % La-Ce incorporation. The cost performance, (BH)max/cost, has been raised by 27.1% compared to a 48.9 MGOe La/Ce-free commercial magnet. The construction of chemical heterogeneity offers recipes to develop commercial-grade PMs using the less risky La/Ce, and also provides a promising solution to the REs availability constraints.

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mentioning

confidence: 99%

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

Jin

Zhang

et al. 2016

Sci Rep

127

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“…On the one hand, the CeFe 2 phase behaves as a paramagnetic phase at 300 K and a soft magnetic phase below 230 K. [41] Hence, its existence is considered as a dilute magnetic phase at room temperature, which is detrimental to the hard magnetic properties below 230 K. On the other hand, it also shows certain advantages in the Nd-Ce-Fe-B magnets for smoothing the grain boundaries during the sintering process, and enhancing the corrosion resistance. [42,43] Thus, understanding the content and magnetism of the REFe 2 phase and its role on the magnetic performance of Nd-Ce-Fe-B becomes a fundamental concern. As shown in Figs.…”

Section: Refe 2 Phasementioning

confidence: 99%

“…[13][14][15][16] However, the phase constitution and microstructure of the Ce-containing magnets differ from those of traditional Pr-Nd-based magnets. [17,18] Furthermore, the hyperfine structures of Ce 2 Fe 14 B and Ce-containing RE 2 Fe 14 B phases have not been completely defined in the last decades as they have few applications. Therefore, the study of hyperfine structures can not only complement the hyperfine structures of the RE 2 Fe 14 B phases, but also reveal the phase constitution and microstructure of the Ce-contained RE-Fe-B magnets.…”

Section: Introductionmentioning

confidence: 99%

⁵⁷Fe Mössbauer spectrometry: A powerful technique to analyze the magnetic and phase characteristics in RE–Fe–B permanent magnets*

et al. 2021

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This review summarizes the recent advances on the application of 57Fe Mössbauer spectrometry to study the magnetic and phase characteristics of Nd–Fe–B-based permanent magnets. First of all, the hyperfine structures of the Ce2Fe14B, (Ce, Nd)2Fe14B and MM2Fe14B phases are well-defined by using the model based on the Wigner-Seitz analysis of the crystal structure. The results show that the isomer shift δ and the quadrupole splitting ΔE Q of those 2:14:1 phases show minor changes with the Nd content, while the hyperfine field B hf increases monotonically with increasing Nd content and its value is influenced by the element segregation and phase separation in the 2:14:1 phase. Then, the hyperfine structures of the low fraction secondary phases are determined by the 57Fe Mössbauer spectrometry due to its high sensitivity. On this basis, the content, magnetic behavior, and magnetization of the REFe2 phase, the amorphous grain boundary (GB) phase, and the amorphous worm-like phase, as well as their effects on the magnetic properties, are systematically studied.

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“…Zhang et al . 10 reported that the REFe 2 phase could improve the wettability of 2:14:1 phase when the magnets are sintered at temperature above the melting point of REFe 2 phase. Our previous work also suggested that Ce atom prefer to enter into the 1:2 phase, which leads the element segregation and increases the Nd content in the (NdCe) 2 Fe 14 B phase 8 .…”

Section: Introductionmentioning

confidence: 99%

Understanding the element segregation and phase separation in the Ce-substituted Nd-(Fe,Co)-B based alloys

Zhao¹,

Zhang²,

Ahmed³

et al. 2018

Sci Rep

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Ce substituted Nd2Fe14B (2:14:1)-type permanent magnets have shown increasing potential in the applications due to their high properties/cost ratio. However, the element segregation and phase separation in the Ce substituted magnets have not been fully understood yet. In this work, (Nd1−xCex)25Fe40Co20Al4B11 alloys with high coercivities were prepared by copper mold casting. Based on detailed microstructure and composition analysis, the segregation of rare earth (RE) elements was observed in the as-cast alloys. Nd element prefers to enter into the 2:14:1 phase and the Ce element enter into the 1:2 phase. The existence of the 1:2 phase can promote the element segregation. The alloy shows an abnormal increase of coercivity from 641 kA/m for x = 0.2 to 863 kA/m for x = 0.3. This increase could be attributed to the phase separation of the 2:14:1 phase, which has been confirmed by the microstructural characterization. The present data provides useful information for exploring Ce-containing Nd-Fe-B magnets.

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Variations of phase constitution and magnetic properties with Ce content in Ce-Fe-B permanent magnets

Cited by 47 publications

References 16 publications

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

⁵⁷Fe Mössbauer spectrometry: A powerful technique to analyze the magnetic and phase characteristics in RE–Fe–B permanent magnets*

Understanding the element segregation and phase separation in the Ce-substituted Nd-(Fe,Co)-B based alloys

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Variations of phase constitution and magnetic properties with Ce content in Ce-Fe-B permanent magnets

Cited by 47 publications

References 16 publications

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

Chemically Inhomogeneous RE-Fe-B Permanent Magnets with High Figure of Merit: Solution to Global Rare Earth Criticality

57Fe Mössbauer spectrometry: A powerful technique to analyze the magnetic and phase characteristics in RE–Fe–B permanent magnets*

Understanding the element segregation and phase separation in the Ce-substituted Nd-(Fe,Co)-B based alloys

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⁵⁷Fe Mössbauer spectrometry: A powerful technique to analyze the magnetic and phase characteristics in RE–Fe–B permanent magnets*