Preparation of Mg-Li-Sm alloys by electrocodeposition in molten salt

Electrocodeposition of Mg-Li-Sm alloys was investigated in molten KCl-LiCl-MgCl2-SmCl3-KF system. The effects of electrolytic temperature and cathodic current density on current efficiency were studied and optimal electrolysis parameters were obtained. The optimum electrolysis condition was a molten salt mixture of LiCl: KCl =50:50 (wt.%), electrolytic temperature: 660 °C, cathode current density: 9.5 A/cm2 and electrolysis time of 40 min. The current efficiency reached 77.3%. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses of the deposits indicated that Mg-Li-Sm alloys, having Mg, βLi and Mg41Sm5 phases, were obtained by electrocodeposition in molten system. The content and distribution of elements in Mg-Li-Sm alloys were analyzed by ICP-MS and EPMA, respectively. The results showed that the distribution of Mg and Sm was homogeneous in the alloys. ICP analyses of samples obtained by electrolysis showed that lithium contents in Mg-Li-Sm alloys could be controlled by MgCl2 concentration and electrochemical parameters. It was proved that preparation of Mg-Li-Sm alloys by electrocodeposition in molten salt was feasible.