Electrochemical behavior of Y（Ⅲ） and preparation of Y-Ni intermetallic compounds in molten LiCl-KCl salts

• Published in: 中国稀土学报：英文版 2017, Vol.35 (1), p.90-97
• Main Author: 韩伟 赵强 王季 李梅 刘文凯 张密林 杨晓光 孙杨
• Format: Article
• Language: English
• Subjects: KCl; LiCl; 制备; 吉布斯自由能; 扫描电子显微镜; 熔融盐; 电化学行为; 金属间化合物
• ISSN: 1002-0721; 2509-4963

The work concerned the electrochemical behaviors of Y（Ⅲ） on W and Ni electrodes in molten LiCl-KCl salts by a series of electrochemical techniques. The electrochemical reaction of Y（Ⅲ） to Y（0） proceeded in a one-step reduction process with the exchange of three electrons, Y（Ⅲ）＋3e^–→Y（0）. Compared with the cyclic voltammogram and square wave voltammogram obtained on W electrode, the reduction potential of Y（Ⅲ） on Ni electrode was observed at less negative potential than the one of Y（Ⅲ） to give pure Y metal on W electrode, which revealed the occurrence of underpotential deposition of Y（Ⅲ） on Ni electrode. Electromotive force（emf） measurements were performed to calculate the relative partial molar Gibbs energies and activities of Y in Y-Ni alloys. The standard Gibbs energies of formation for different Y-Ni intermetallic compounds were also estimated. The different Y-Ni alloys were formed by potentiostatic electrolysis at different potentials and characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy dispersive spectrometry（EDS）. It was found that four intermetallic compounds, YNi5, Y2Ni7, YNi3 and YNi2, were selectively produced by controlling applied potential.