Electrochemical formation of Dy-Ni alloys in molten NaCl-KCl-DyCl3

The electrochemical formation of Dy-Ni alloys was investigated in a molten NaCl-KCl-DyCl3 (0.50 mol%) system at 973 K. Cyclic voltammetry and open-circuit potentiometry at a Ni electrode indicated the formation of several Dy-Ni alloy phases. Alloy samples were prepared by one- or two-step potentiostatic electrolysis of a Ni plate electrode at various potentials. Scanning electron microscopy observations and X-ray diffraction measurements confirmed the formation of DyNi2, DyNi3, Dy2Ni7, and DyNi5. The formation reactions of the Dy-Ni alloys and the corresponding potentials were determined, and the optimum electrolysis conditions for the separation of Nd and Dy from molten salts containing both Nd(III) and Dy(III) ions are discussed.