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