Electrochemical Synthesis and Thermodynamic Properties of Pr‐Ni Intermetallic Compounds in a LiCl‐KCl‐NiCl2‐PrCl3 Melt

Abstract In this report, the electrochemical behaviors of Pr(III) and Ni(II) ions on a W electrode were investigated in LiCl‐KCl eutectic by cyclic voltammetry (CV), square wave voltammetry (SWV), chronopotentiometry (CP) and open‐circuit chronopotentiometry (OCP) techniques. From the results of electrochemical methods, different signals corresponding to seven kinds of intermetallic compounds in the phase diagram of Pr−Ni were observed. The thermodynamic properties of intermetallic compounds in the temperature range of 823–923 K were investigated by open‐circuit chronopotentiometry. With the evaluated apparent standard potentials of Pr−Ni intermetallic compounds, the Gibbs energies, enthalpies and entropies of formation were also calculated. The co‐reduction products by galvanostatic and potentiostatic electrolysis were characterized based on X‐ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive X‐ray spectroscopy (EDS). The shape of the alloy obviously changes from granular to bulk, and the alloy phase changes from Pr‐rich to Ni‐rich. The co‐reduction products of PrNi 5 , PrNi 2 and PrNi were identified.