Advances in Molten Salts

ISBN Print: 1-56700-142-4

Deposition of lanthanide and Yttrium Ions at Molten Metal Electrodes and Alloying

Résumé

The deposition potentials of lanthanide ions at molten A1 electrodes and the deposition potentials of neodymium and yttrium ions at molten Sb, Bi, Ga, Sn, Zn, Pb and In electrodes in equimole NaCl-KCl melt have been measured by potential scanning voltammetry. The electrochemical deposition potentials have been plotted with atomic numbers of lanthanide metals and the “double peak effect ” appears, which has been preliminarily discussed in terms of the electronic structure and properties of lanthanide metals. Differences between the values of the deposition potential at the molten metal electrodes and those at the inert Mo electrodes are related to the alloying of the deposited rare earth elements with the electrodes, shifting the deposition potentials to the positive direction. The standard electrode potentials of rare earth elements measured in molten salt, for example, Dy/Dy(Ⅲ), Y/Y(Ⅲ), Ho/Ho(Ⅲ) and Nd/Nd(Ⅲ) are all more negative than the theoretical ones, which may be related to the molten salt solvation. The differences between the experimental values and theoretical ones may be regarded as an index of solvation degree.