Electrochemical Behaviour Of Cerium (Ⅲ) And Co-deposition Of Mg-Li-Ce And Al-Li-Ce In Molten Salts

The electrochemical behaviour of Ce（Ⅲ） ions was investigated in the LiCl–KCl moltensalts on different electrodes in500–650℃using cyclic voltammetry, square wavevoltammetry, chronopotentiometryand chronopotentiometry. The reaction mechanism andtransport parameters of electroactive species were determined by transient electrochemicaltechniques at a molybdenum electrodes, the mechanism of electrochamical co-deposition ofternary Mg–Li–Ce and Al-Li-Ce alloys were studied in LiCl–KCl–MgCl₂,LiCl–KCl–AlCl₃and LiCl–KCl–AlCl₂–CeO₂melts containing the Ce（Ⅲ） ions. X–ray diffraction （XRD）, scanelectron micrograph （SEM）, energy dispersive spectrometry （EDS） and inductively coupledplasma atomic emission spectrometer （ICP-AES） were employed to characterize the alloys.The electrochemical behaviour of cerium（Ⅲ） was investigated in the LiCl–KCl eutecticmixture on molybdenum, nickel, magnesium and aluminium electrodes in the500-650℃temperature range. On Mo electrode, the study showed that Ce（Ⅲ） ions were reduced into Cemetal in a one-step diffusion-controlled process exchanging three electrons: Ce（Ⅲ）+3e-Ce.The diffusion coefficients verify the Arrhenius law, allowing the activation energy tobecalculated. The study of the electrochemical reduction of Ce （Ⅲ） ions on reactive electrodes（Ni, Mg, Al）. Frst by cyclic voltammetry showed that the reduction potential of Ce（Ⅲ）/Ce onreactive electrodes was observed at more positive values than those on inert electrode and andformed intermetallic compound on active electrodes. Preparation of alloys layers was finallycarried out by intentiostatic electrolyses at under potential compared to the pure metaldeposition. The polarization behaviour of cerium（Ⅲ） was investigated in the LiCl–KCleutectic mixture on aluminium electrodes in the500⁵90℃the temperature range.The studyshowed that as the temperature gradually raised, polarization value to reduce gradually.The electrochemical codeposition of Mg, Li and Ce was investigated on a molybdenumelectrode in LiCl–KCl–0.32wt.%MgCl₂–3.23wt.%CeCl₃melts at600℃indicated that theelectrochemical codeposition of Mg, Li and Ce metal occurred at current densities lower than–0.32A cm-2or at an applied potential more negative than–2.4V vs. Ag/AgCl. XRD resultssuggested that Mg₁₇Ce₂and Mg3Ce were formed in Mg–Li–Ce alloys. The analysis of SEMand EDS showed that the Ce intermetallic compounds showed a distribution in grainboundaries of Mg-Li alloy. The electrochemical codeposition of Al, Li and Ce was investigated on a molybdenumelectrode in LiCl–KCl–AlCl₂–CeCl₃and LiCl–KCl–AlCl₂–CeO₂melts at550℃showedthat the electrochemical codeposition of Al, Li and Ce metal occurred at current densitieslower than–0.37A cm-2. XRD results suggested that Al92Ce8, Al4Ce, Al3Ce and Al2Li3wereformed in Al–Li–Ce alloys.