Determination of activity of RE (RE = Nd and Dy) in molten RE‒Fe‒B alloys by the electromotive force method

Daisuke Noguchi; Osamu Takeda; Taichi Abe; Hongmin Zhu; Satoshi Sugimoto

doi:10.1016/j.tca.2022.179161

Determination of activity of RE (RE = Nd and Dy) in molten RE‒Fe‒B alloys by the electromotive force method

Daisuke Noguchi, Osamu Takeda, Taichi Abe, Hongmin Zhu, Satoshi Sugimoto

Research output: Contribution to journal › Article › peer-review

Abstract

Considerable discrepancy was observed in the measured activity (chemical potential) of Nd reported in the literatures on molten Nd‒Fe system. The activity of Nd in molten Nd‒Fe(‒B) alloys was measured by the electromotive force (EMF) method using a specially-fabricated Nd concentration cell. The activity of Dy in molten Dy‒Fe(‒B) alloys was also investigated for verification. The measured activity of Nd in the molten Nd‒Fe(‒B) alloys was close to that observed in the ideal solution, which was in accordance with the data reported by Hennemann et al. The presence of B in the molten alloys did not significantly influence the activity of Nd in the studied concentration range. The measured activity of Dy in Dy‒Fe(‒B) alloys was similar to that observed in the ideal solution. The results obtained were consistent with the latest phase diagram studies, including the assessments that applied the Calphad technique.

Original language	English
Article number	179161
Journal	Thermochimica Acta
Volume	709
DOIs	https://doi.org/10.1016/j.tca.2022.179161
Publication status	Published - 2022 Mar

Keywords

Activity
Dysprosium
Electromotive force method
Nd magnet
Nd-rich phase
Neodymium

ASJC Scopus subject areas

Instrumentation
Condensed Matter Physics
Physical and Theoretical Chemistry

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10.1016/j.tca.2022.179161

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title = "Determination of activity of RE (RE = Nd and Dy) in molten RE‒Fe‒B alloys by the electromotive force method",

abstract = "Considerable discrepancy was observed in the measured activity (chemical potential) of Nd reported in the literatures on molten Nd‒Fe system. The activity of Nd in molten Nd‒Fe(‒B) alloys was measured by the electromotive force (EMF) method using a specially-fabricated Nd concentration cell. The activity of Dy in molten Dy‒Fe(‒B) alloys was also investigated for verification. The measured activity of Nd in the molten Nd‒Fe(‒B) alloys was close to that observed in the ideal solution, which was in accordance with the data reported by Hennemann et al. The presence of B in the molten alloys did not significantly influence the activity of Nd in the studied concentration range. The measured activity of Dy in Dy‒Fe(‒B) alloys was similar to that observed in the ideal solution. The results obtained were consistent with the latest phase diagram studies, including the assessments that applied the Calphad technique.",

keywords = "Activity, Dysprosium, Electromotive force method, Nd magnet, Nd-rich phase, Neodymium",

author = "Daisuke Noguchi and Osamu Takeda and Taichi Abe and Hongmin Zhu and Satoshi Sugimoto",

note = "Funding Information: The authors are grateful to Mr. Y. Yokoyama and Dr. E. Nakamura (Santoku Co., Ltd.) for supplying the alloy samples. This work was supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM) , Grant number JPMXP0112101004 , through the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japanese Goverment. Publisher Copyright: {\textcopyright} 2022 Elsevier B.V.",

year = "2022",

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doi = "10.1016/j.tca.2022.179161",

language = "English",

volume = "709",

journal = "Thermochimica Acta",

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T1 - Determination of activity of RE (RE = Nd and Dy) in molten RE‒Fe‒B alloys by the electromotive force method

AU - Noguchi, Daisuke

AU - Takeda, Osamu

AU - Abe, Taichi

AU - Zhu, Hongmin

AU - Sugimoto, Satoshi

N1 - Funding Information: The authors are grateful to Mr. Y. Yokoyama and Dr. E. Nakamura (Santoku Co., Ltd.) for supplying the alloy samples. This work was supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM) , Grant number JPMXP0112101004 , through the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japanese Goverment. Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/3

Y1 - 2022/3

N2 - Considerable discrepancy was observed in the measured activity (chemical potential) of Nd reported in the literatures on molten Nd‒Fe system. The activity of Nd in molten Nd‒Fe(‒B) alloys was measured by the electromotive force (EMF) method using a specially-fabricated Nd concentration cell. The activity of Dy in molten Dy‒Fe(‒B) alloys was also investigated for verification. The measured activity of Nd in the molten Nd‒Fe(‒B) alloys was close to that observed in the ideal solution, which was in accordance with the data reported by Hennemann et al. The presence of B in the molten alloys did not significantly influence the activity of Nd in the studied concentration range. The measured activity of Dy in Dy‒Fe(‒B) alloys was similar to that observed in the ideal solution. The results obtained were consistent with the latest phase diagram studies, including the assessments that applied the Calphad technique.

AB - Considerable discrepancy was observed in the measured activity (chemical potential) of Nd reported in the literatures on molten Nd‒Fe system. The activity of Nd in molten Nd‒Fe(‒B) alloys was measured by the electromotive force (EMF) method using a specially-fabricated Nd concentration cell. The activity of Dy in molten Dy‒Fe(‒B) alloys was also investigated for verification. The measured activity of Nd in the molten Nd‒Fe(‒B) alloys was close to that observed in the ideal solution, which was in accordance with the data reported by Hennemann et al. The presence of B in the molten alloys did not significantly influence the activity of Nd in the studied concentration range. The measured activity of Dy in Dy‒Fe(‒B) alloys was similar to that observed in the ideal solution. The results obtained were consistent with the latest phase diagram studies, including the assessments that applied the Calphad technique.

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KW - Nd-rich phase

KW - Neodymium

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Determination of activity of RE (RE = Nd and Dy) in molten RE‒Fe‒B alloys by the electromotive force method

Abstract

Keywords

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