Morphology Control of Dy-Ni Alloy Films by Electrochemical Displantation

Konishi, Hisatoshi; Ito, Yasuhiko

doi:10.1149/1.1516413

Cited by 30 publications

(25 citation statements)

References 7 publications

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“…The molten salt electrochemical process has been studied by Ito and co-workers including the present authors (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and many other researchers (13)(14)(15)(16). The present authors reported a unique phenomenon during the electrochemical formation of Dy-Ni alloys in molten LiCl-KCl-DyCl 3 : DyNi 2 film with thickness of 60 µm was formed in 2 h at 700 K (1).…”

Section: Introductionmentioning

confidence: 64%

(Keynote) Separation of Dy and Nd (La) Using Molten Salt and an Alloy Diaphragm

Konishi

Ono

Oishi³

2013

ECS Trans.

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Cyclic voltammetry was conducted using a Ni electrode in molten LiCl-KCl-RECl 3 (RE=Dy, Nd) systems at 723 K. In cathodic scan, a cathodic current was observed from 1.00 V (vs. Li + /Li) due to the formation of Dy-Ni alloys in a molten LiCl-KCl-DyCl 3 system. In contrast, a cathodic current was observed from 0.60 V due to the formation of Nd-Ni alloys in a molten LiCl-KCl-NdCl 3 system. On the basis of these results, an alloy sample was prepared by potentiostatic electrolysis at 0.65 V for 1 h using a Ni plate cathode in a molten LiCl-KCl-DyCl 3 -NdCl 3 system. The mass ratio of Dy/Nd in the alloy sample was found to be 72 by ICP-AES. Another investigation was conducted in a molten LiCl-KCl-DyCl 3 -LaCl 3 system, with and without FeCl 2 addition. Regardless of the presence of FeCl 2 , DyNi 2 was selectively formed on a Ni plate cathode at 0.55 V.

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Section: Introductionmentioning

confidence: 64%

(Keynote) Separation of Dy and Nd (La) Using Molten Salt and an Alloy Diaphragm

Konishi

Ono

Oishi³

2013

ECS Trans.

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“…Through electrochemical method in molten salts, Ln and their alloys can be prepared with high purity and more maneuverability [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and electrochemical properties of holmium and HoxAly intermetallic compounds in the LiCl-KCl eutectic

Liu

Yuan

Wang

et al. 2015

Electrochimica Acta

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13] So far, various kinds of RE-TM alloys, where RE = Sc, Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er, and TM = Fe, Co, Ni, and Pd, have been successfully obtained mainly from molten LiCl-KCl-RECl 3 systems at 723-773 K.…”

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confidence: 99%

Electrochemical Formation and Phase Control of Pr-Ni Alloys in a Molten LiCl-KCl-PrCl[sub 3] System

Nohira

Kambara

Amezawa

et al. 2005

J. Electrochem. Soc.

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The electrochemical formation of Pr-Ni alloys was investigated in a molten LiCl-KCl-PrCl 3 ͑0.50 mol %͒ system at 723 K. A coherent and dense PrNi 2 film was rapidly formed on a Ni electrode by potentiostatic electrolysis at 0.50 V. When a thin Ni electrode ͑50 m͒ was used, PrNi was formed at 0.50 V after the whole electrode became PrNi 2 . The formed PrNi 2 electrodes were transformed to other phases, i.e., PrNi 3 , Pr 2 Ni 7 , PrNi 5 , and Ni, by electrochemical displantation. The formation reactions of the alloys and the corresponding equilibrium potentials were clarified. From morphological and crystallographic investigations using transmission electron microscopy and electron diffraction, it has been suggested that the rapid PrNi 2 formation is due to the high Pr diffusivity in and near the grain boundaries.The present authors have been studying the electrochemical formation of rare earth ͑RE͒-transition metal ͑TM͒ alloys in molten chlorides, in which the alloy formation is attained by cathodic reduction of rare earth ions on a transition metal substrate. 1-13 So far, various kinds of RE-TM alloys, where RE = Sc, Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er, and TM = Fe, Co, Ni, and Pd, have been successfully obtained mainly from molten LiCl-KCl-RECl 3 systems at 723-773 K.During a series of such studies, the authors found that only the RENi 2 phase was preferentially formed, although there were several other alloy phases in the phase diagrams. The growth rate of the RENi 2 phase by the electrochemical process was extremely high compared to those measured by a diffusion couple method at almost the same temperatures. 14,15 For instance, in the case of YNi 2 formation, the alloy film of 400 m was formed only in 20 h at 773 K. 1 In addition, from our recent studies on the electrochemical formation of the DyNi 2 , it was found that the growth rate strongly depends on the electrolysis potential; the DyNi 2 films 60, 30, and 20 m thick were formed at 0.55, 0.62, and 0.70 V ͑vs. Li + /Li͒, respectively, for 2 h. 5,9 Because such features, i.e., rapid, preferential, and potential-dependent growths, are not found in conventional alloy formation processes, the electrochemical RENi 2 formation is worth studying from both scientific and engineering aspects. 3-5 Concerning the mechanism of DyNi 2 film growth, the authors indicated that the high growth rate might be due to the high Dy diffusivity in and near the grain boundaries. 9 The molecular dynamics simulation on YNi 2 also suggested that the rapid growth was mainly due to the high-rate diffusion in and near the grain boundaries. 16 In our previous studies it was also found that anodic polarization of the formed RENi 2 resulted in the rapid dissolution of RE to form other RE-Ni phases. 2,5 In the case of Dy-Ni alloys, the formed DyNi 2 films were transformed to porous DyNi 3 , Dy 2 Ni 7 , DyNi 5 , and Ni films depending on the electrolysis potential. 5 It was also shown that there was a possibility to control simultaneously morphology ͑porosity, pore size͒ and phase state o...

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Morphology Control of Dy-Ni Alloy Films by Electrochemical Displantation

Cited by 30 publications

References 7 publications

(Keynote) Separation of Dy and Nd (La) Using Molten Salt and an Alloy Diaphragm

(Keynote) Separation of Dy and Nd (La) Using Molten Salt and an Alloy Diaphragm

Thermodynamic and electrochemical properties of holmium and HoxAly intermetallic compounds in the LiCl-KCl eutectic

Electrochemical Formation and Phase Control of Pr-Ni Alloys in a Molten LiCl-KCl-PrCl[sub 3] System

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