Electrochemical Formation and Phase Control of Pr-Ni Alloys in a Molten LiCl-KCl-PrCl[sub 3] System

The electrochemical formation of Pr-Ni alloys was investigated in a molten system at . A coherent and dense film was rapidly formed on a Ni electrode by potentiostatic electrolysis at . When a thin Ni electrode was used, PrNi was formed at after the whole electrode became . The formed electrodes were transformed to other phases, i.e. , , , , and Ni, by electrochemical displantation. The formation reactions of the alloys and the corresponding equilibrium potentials were clarified. From morphological and crystallographic investigations using transmission electron microscopy and electron diffraction, it has been suggested that the rapid formation is due to the high Pr diffusivity in and near the grain boundaries.