Electrochemical Co-Deposition of Mg–Ca Alloys from KCl–CaCl2–MgCl2 Melts

Abstract

This work reports the electrochemical fabrication of Mg–Ca alloys by co-deposition of Mg and Ca ions in KCl–CaCl2–MgCl2 melts at 943 K on tungsten electrodes. Cyclic voltammetry indicated that co-reduction of Mg(II) and Ca(II) ions occurs at about −2.23 V in KCl–CaCl2 eutectic melts at 943 K. The diffusion coefficient of Mg(II) in KCl–CaCl2 eutectic melts was determined by chronopotentiometry with Sand's equation. Open-circuit chronopotentiometry was applied to evaluate the equilibrium potential of Mg(II)/Mg(0) system. Bulk products of Mg–Ca alloys were obtained by galvanastatic electrolysis at 6.00 A cm−2 on tungsten electrodes. The compositions of obtained Mg–Ca alloys were analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES). X-ray diffraction (XRD) indicates that Mg–Ca alloys mainly comprise α-Mg and Mg2Ca phases. The microstructure and micro-zone chemical analysis of Mg–Ca alloys were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) analysis.