2022 年 22 巻 1 号 p. 23-28
The electrochemical formation of Ce-Ni alloys was investigated in a molten LiCl-KCl-CeCl3 at 723 K under an Ar gas atmosphere. Open-circuit potentiometry was performed with a Ni electrode after electrodepositing Ce metal at 0.40 V (vs. Li+/Li) for 20 s. Four potential plateaus were observed at 0.54 V, 0.72 V, 1.19 V and 1.64 V, which were considered to correspond to the potentials of two-phase coexisting states of different Ce–Ni alloys. Potentiostatic electrolysis was conducted at 0.50 V for 1 h using Ni plate electrodes, and XRD analysis indicated the formation of CeNi2. After the formation of CeNi2 on the Ni plate electrodes, potentiostatic electrolysis was also conducted at 0.65 V, 0.80 V, 1.40 V and 2.00 V for 1 h. The formed CeNi2 was transformed to CeNi3 at 0.65 V, Ce2Ni7 at 0.80 V, CeNi5 at 1.40 V and Ni at 2.00 V. On the other hand, an alloy sample was prepared at 0.50-0.60 V for 1 h using a Ni electrode in molten LiCl-KCl-CeCl3(0.50 mol%)-LaCl3(0.50 mol%). The highest mass ratio of Ce/La in the alloy samples was 84 at 0.51-0.53 V.