New Mathematical Formulation for the Deposition Potential and Atomic Radius: Theoretical Background and Applications to Sn-Ln Intermetallic Compounds

作者：Xu, Hengbin; Zhang, Milin^*; Yan, Yongde; Ji, Debin^*; Wang, Pu; Qu, Min; Liu, Li

来源：Journal of Physical Chemistry C, 2018, 122(6): 3463-3470.

DOI：10.1021/acs.jpcc.7b11782

• EUTECTIC LICL-KCL
• RARE-EARTH-ELEMENTS
• SALT ELECTROCHEMICAL PROCESS
• THERMOCHEMICAL PROPERTIES
• THERMODYNAMIC PROPERTIES
• PYROCHEMICAL PROCESSES
• MOLTEN FLUORIDES
• PHASE-CONTROL
• ALLOY-FILMS
• BEHAVIOR

Purification of rare earth elements is challenging due to their chemical similarities. The interaction and behavior of alloys involving stannous chloride (SnCl2) and lanthanide metals are discussed in the present paper. We investigate the quantitative relationship between the deposition potential of lanthanides with SnCl2 and atomic radius by employing electrochemical techniques, involving cyclic voltammetry (CV), square wave voltammetry (SWV) and open-circuit chronopotentiometry (OCP). Our electrochemical study on the formation intermetallic compounds is based on Sn in LiCI-KCI melts on molybdenum electrodes at 873 K With the same experimental conditions, different deposits (e.g., Sn-La, Sn-Pr, Sn-Gd, Sn-Dy and Sn-Er) were obtained by using identical substrates. We establish the relationship between the deposition potential and the atomic radii of lanthanides by deriving a mathematical equation from the sorting out and summarizing of the data. The predictions for the existence and the deposition potentials of unknown intermediate phases (e.g., Sn Ce, Sn Nd, Sn Yb and Sn Lu) were made. From our results, open-circuit chronopotentiometry is potentially a valuable methodology to formally verify the correctness of the forecast. X-ray diffraction pattern (XRD), scanning electron micrograph (SEM) and energy-dispersive spectrometry (EDS) data further verify the reliability of the linear equation.

• 出版日期2018-2-15
• 单位黑河学院; 哈尔滨工程大学