Preparation of rare earth alloys by cathodic alloying

Rare earth alloys were formed by the reduction of electrode processes of La(111), Ce(111), Pr(111), Nd(111) and Y(111) on Fe, Co, Ni and Cu cathodes in chloride melts. Cyclic voltammetry and potential-time curves were used to interpret results. The order of magnitude for the diffusion coefficients of La, Pr, Nd and Y in alloyed cathode was found to be 10 exp -11 cm exp 2 s exp -1 . Free energy of formation for the intermetallic compound of rare earth with Cu or Fe metal was determined by the potential-time curve after potentiostatic electrolysis. Thirteen surface alloy layers were obtained by electrolysis at constant potential. The alloys La-Fe, La-Ni, La-Cu, Pr-Cu, Pr-Fe, Pr-Co, Pr-Ni, Nd-Fe, and Nd-rich RE-Fe were prepared by consumable cathode. Most of the alloys contained rare earths over 90 wt%. Current efficiencies reached 85-90%. Recoveries of rare earths reached 90%.