Mechanistic Insight into Electrochemical Synthesis of LaNi5 in a Eutectic CaCl2-NaCl Melt at 850°C

LaNi5 alloy powders were prepared by electro-deoxidation of the oxide precursors in a eutectic CaCl2-NaCl melt at 850°C. The reduction pathway from the mixture of La3Ni2O7 and NiO to LaNi5 was studied by examination of partially reduced samples using XRD, SEM and EDX analysis, which were obtained by interrupting the reduction process after different reduction times. The first stage of the reaction involved the rapid formation of Ni and of LaOCl, then LaOCl and La2O3 were electrochemically reduced and alloyed with Ni particles nearby along with their surface. The morphology of LaNi5 particles reduced for the different durations of reduction can be changeable.