Electrochemical codeposition of typical α+β phases Mg-Li alloys from the molten LiCl-KCl-MgCl_2 system

Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl（50 wt.%：50 wt.%） melts containing different concentrations of MgCl2 at 973 K.Cyclic voltammograms show that the underpotential deposition of lithium on pre-deposited magnesium leads to the formation of liquid Mg-Li alloys.The deposition potentials of Mg（II） and Li（I） ions gradually near each other with MgCl2 concentration decreasing.Mg-Li alloys with typical α ＋ β phases could be obtained by potentiostatic electrolysis from LiCl-KCl melts containing 5 wt.% MgCl2 at -2.25 V vs.Ag/AgCl（cathodic current density 1.70 A·cm-2） for 2.5 h.α phase, α ＋ β phases, and β phase Mg-Li alloys with different lithium contents were obtained by potentiostatic electrolysis from LiCl-KCl melts with the different concentrations of MgCl2.The samples were characterized by X-ray diffraction and scanning electron microscopy.

Electrochemical behaviour and codeposition of Al-Li-Er alloys in LiCl-KCl-AlCl_3-Er_2O_3 melts

The electrochemical behaviour of Al, Li, and Er were investigated by electrochemical techniques, such as cyclic voltammograms, chronopotentiometric, chronoamperograms, and open circuit chronopotentiogram on molybdenum electrodes. The results showed that the underpotential deposition of erbium on pre-deposited Al electrodes formed two Al-Er intermetallic compounds. The codeposition of Al, Li, Er occurred and formed Al-Li-Er alloys in LiCl-KCl-AlCl3 -Er2O3 melts at 773K. Different phases such as Al2Er, Al2Er3 and βLi phase of Al-Li-Er alloys were prepared by galvanostatic electrolysis and characterized by X-ray diffraction （XRD）. Scanning electron microscopy （SEM） indicated that Er element mainly distributed at the grain boundary. ICP analyses showed that lithium and erbium contents of Al-Li-Er alloys could be controlled by AlCl3 and Er2O3 concentration and electrochemical parameters.

Electrochemical formation of Mg-Li-Y alloys by co-deposition of magnesium, lithium and yttrium ions in molten chlorides

An electrochemical approach for the preparation of Mg-Li-Y alloys via co-reduction of Mg, Li, and Y on a molybdenum electrode in LiCl-KCl-MgCl2-YCl3 melts at 943 K was investigated. Cyclic voltammograms （CVs） illuminated that the underpotential deposition （UPD） of yttrium on pre-deposited magnesium led to the formation of a liquid Mg-Y alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Y led to the formation of a liquid Mg-Li-Y alloy. Chronopotentiometry measurements indicated that the order of electrode reactions was as follows： discharge of Mg（II） to Mg-metal, electroreduction of Y on the surface of Mg with formation of ε-Mg24＋xY5 and after that the discharge of Li＋ with the deposition of Mg-Li-Y alloys. X-ray diffraction （XRD） indicated that Mg-Li-Y alloys with different phases were formed via galvanostatic electrolysis. The microstructure of different phases of Mg-Li-Y alloys was characterized by optical microscope （OM） and scanning electron microscopy （SEM）. The analysis results of inductively coupled plasma atomic emission spectrometer （ICP-AES） showed that the chemical compositions of Mg-Li-Y alloys corresponded with the phase structures of the XRD patterns, and the lithium and yttrium contents of Mg-Li-Y alloys depended on the concentrations of MgCl2 and YCl3 .

Electrochemical study on preparation of Mg-Li-Yb alloys in LiCl-KCl-KF-MgCl_2-Yb_2O_3 melts

This paper presented a novel study on electrochemical codeposition of Mg-Li-Yb alloys in LiCl-KCl-KF-MgCl2-Yb2O3 melts on molybdenum. The factors of the current efficiency were investigated. Electrolysis temperature had great influence on current efficiency; the highest current efficiency was obtained when electrolysis temperature was about 660 oC. The content of Li in Mg-Li-Yb alloys increased with the high current densities. The optimal electrolytic temperature and cathodic current density were around 660 oC and 9.3 A/cm2, respectively. The chemical content, phases, morphology of the alloys and the distribution of the elements were analyzed by X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry, respectively. The intermetallic of Mg-Yb was mainly distributed in the grain boundary of the alloys, presented as reticulated structures, and refined the grains. The lithium and ytterbium contents in Mg-Li-Yb al-loys could be controlled by changing the concentration of MgCl2 and Yb2O3 and the electrolysis conditions.