Electrochemical co-reduction of holmium and magnesium ions in eutectic LiCl-KCl salts

The electrochemical co-reduction of Ho(Ⅲ)and Mg(Ⅱ)ions was investigated on Mo electrode in eutectic LiCl–KCl salts at temperature of 773 K using various electrochemical techniques.Cyclic voltammogram(CV)and square wave voltammogram exhibit three reduction peaks corresponding to the reduction of Ho(Ⅲ)on pre-deposited Mg electrode,whose potentials are more positive than that of Ho on Mo electrode because of the formation of Mg-Ho intermetallic compounds by co-reduction of Ho(Ⅲ)and Mg(Ⅱ)ions.Meanwhile,chronopotentiometry and open-circuit chronopotentiometry were used to explore the electrochemical formation of Mg–Ho intermetallics.Mg–Ho alloys were produced by galvanostatic electrolysis at the current of 1.5 A for different electrolysis durations.Ho_(5)Mg_(24),HoMg_(2) and HoMg intermetallic compounds were acquired and characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM)coupled with energy-dispersive spectroscopy(EDS).The results indicate that Mg–Ho intermetallic compounds,Ho_(5)Mg_(24),HoMg_(2) and HoMg,could be prepared by molten salts electrolysis.