Electrochemical Formation of Dy-Ni Alloys in Molten LiF-CaF₂-DyF₃

Abstract

The electrochemical formation of Dy-Ni alloys was investigated in a molten LiF-CaF2-DyF3 (0.30 mol%) system at 1123 K. Cyclic voltammetry and open-circuit potentiometry indicated the formation of several phases of Dy-Ni alloys. Potentiostatic electrolysis was conducted to prepare an alloy sample using a Ni-plate electrode at 0.20 V vs. Li+/Li for 120 min. Cross-sectional scanning electron microscopy revealed that the Ni plate was partially transformed into a Dy-Ni alloy. X-ray diffraction analysis confirmed that DyNi2 was the predominant phase and DyNi3 the minor phase in the alloy. When the electrolytic potential was kept at 0.45 V and 0.62 V for 110 min after electrolysis at 0.20 V for 130 min, the resultant phases were DyNi3 and DyNi5, respectively. The formation potential for each Dy-Ni alloy phase was determined from the experimental results.