Electrochemical Formation of RE-Cu (RE=Dy, Nd) Alloys in a Molten LiCl-KCl System

Abstract

The electrochemical formation of RE-Cu (RE=Dy, Nd) alloys were investigated in a molten LiCl-KCl-RECl3 (0.50 mol% added) at 723 K. Open-circuit potentiometry was carried out with a Cu electrode after depositing Dy metal by potentiostatic electrolysis at 0.40 V (vs. Li+ / Li) for 120 s in a molten LiCl-KCl-DyCl3(0.50 mol%) at 723 K. There were four potential plateaus at (a) 0.50 V, (b) 0.68 V, (c) 0.88 V and (d) 0.95 V. An alloy sample was prepared at 0.55 V for 4 h. From the XRD pattern of the sample, the alloy phase was identified as DyCu2. In the sample obtained at 0.78 V, the existence of DyCu5 was seen. The phase of the sample obtained at 1.50 V was transformed to Cu. On the basis of these results, alloy samples were prepared by potentiostatic electrolysis at 0.45-0.75 V for 1 h using Cu plates in a molten LiCl-KCl-DyCl3-NdCl3. The mass ratios of Dy/Nd in the alloy samples were found to be 6-12 by ICP-AES.