Electrochemical formation process and phase control of Mg-Li-Ce alloys in molten chlorides

An electrochemical approach for the preparation of Mg-Li-Ce alloys by co-reduction of Mg, Li and Ce on a molybdenum electrode in KCl-LiCl-MgCl2-CeCl3 melts at 873 K was investigated. Cyclic voltammograms （CVs） and square wave voltammograms indicated that the underpotential deposition （UPD） of cerium...

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Published inJournal of rare earths Vol. 31; no. 6; pp. 609 - 615
Main Author 张萌 韩伟 张密林 朱凤艳 薛云 张志俭
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.06.2013
Subjects
Alloys
Ce（Ⅲ）
Chemical vapor synthesis
Discharge
electrochemical co-deposition
Electrodes
Formations
Magnesium
Magnesium base alloys
Mg-Li-Ce alloys
molten salt
Rare earth metals
rare earths
Underpotential deposition
合金
氯化物
氯化铈
氯化锂
氯化镁
电化学方法
相位控制
underpotential deposition
Mg-Li-Ce alloys
molten salt
electrochemical co-deposition
rare earths
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Summary:An electrochemical approach for the preparation of Mg-Li-Ce alloys by co-reduction of Mg, Li and Ce on a molybdenum electrode in KCl-LiCl-MgCl2-CeCl3 melts at 873 K was investigated. Cyclic voltammograms （CVs） and square wave voltammograms indicated that the underpotential deposition （UPD） of cerium on pre-deposited magnesium led to the formation of Mg-Ce alloys at electrode potentials around –1.87 V. The order of electrode reactions was as follows： discharge of Mg（II） to Mg-metal, UPD of Ce on the surface of pre-deposited Mg with formation of Mg-Ce alloys, discharge of Ce（III） to Ce-metal and after that the discharge of Li＋ with the deposition of Mg-Li-Ce alloys, which was investigated by CVs, chronoamperometry, chronopotentiometry and open circuit chronopotentiometry. X-ray diffraction （XRD） illuminated that Mg-Li-Ce alloys with different phases were obtained via galvanostatic electrolysis by different current densities. The microstructures of Mg-Li-Ce alloys were characterized by optical microscopy （OM） and scanning electron microscopy （SEM）, respectively. The analysis of energy dispersive spectrometry （EDS） showed that Ce existed at grain boundaries to restrain the grain growth. The compositions and the average grain sizes of Mg-Li-Ce alloys could be obtained controllably corresponding with the phase structures of the XRD patterns.
Bibliography:An electrochemical approach for the preparation of Mg-Li-Ce alloys by co-reduction of Mg, Li and Ce on a molybdenum electrode in KCl-LiCl-MgCl2-CeCl3 melts at 873 K was investigated. Cyclic voltammograms （CVs） and square wave voltammograms indicated that the underpotential deposition （UPD） of cerium on pre-deposited magnesium led to the formation of Mg-Ce alloys at electrode potentials around –1.87 V. The order of electrode reactions was as follows： discharge of Mg（II） to Mg-metal, UPD of Ce on the surface of pre-deposited Mg with formation of Mg-Ce alloys, discharge of Ce（III） to Ce-metal and after that the discharge of Li＋ with the deposition of Mg-Li-Ce alloys, which was investigated by CVs, chronoamperometry, chronopotentiometry and open circuit chronopotentiometry. X-ray diffraction （XRD） illuminated that Mg-Li-Ce alloys with different phases were obtained via galvanostatic electrolysis by different current densities. The microstructures of Mg-Li-Ce alloys were characterized by optical microscopy （OM） and scanning electron microscopy （SEM）, respectively. The analysis of energy dispersive spectrometry （EDS） showed that Ce existed at grain boundaries to restrain the grain growth. The compositions and the average grain sizes of Mg-Li-Ce alloys could be obtained controllably corresponding with the phase structures of the XRD patterns.
11-2788/TF
Mg-Li-Ce alloys; molten salt; underpotential deposition; electrochemical co-deposition; rare earths
ZHANG Meng , HAN Wei , ZHANG Milin , ZHU Fengyan , XUE Yun , ZHANG Zhijian （1. Key Discipline Laboratory of Nuclear Safety and Simulation Technology, Harbin Engineering University, Harbin 150001, China; 2. Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China）
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ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(12)60329-9