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

摘要

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 oC,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.