In situ X-ray diffraction analysis of electrochemical Dy-Ni alloying in molten LiCl-KCl

In situ energy-dispersive X-ray diffraction was employed to investigate electrochemical Dy-Ni alloying in molten LiCl-KCl at 723 K. This enabled the determination of the crystal structures and orientations of the products formed during molten salt electrolysis, while also eliminating the effects of the post-electrolysis processes (such as cooling and washing) that are necessary in ex situ measurements. The diffraction peak intensities of DyNi2 generally increased during potentiostatic electrolysis at 0.50 V vs. Li+/Li, whereas the Ni diffraction peak intensities gradually decreased. Furthermore, the intensity of the X-ray fluorescence peak of Dy gradually increased. Thus, DyNi2 could be directly formed from Ni via electrolysis, as no diffraction peaks corresponding to materials other than Ni and DyNi2 were observed. Moreover, (022)-oriented DyNi2 grew preferentially on the (200)-oriented Ni substrate.