Electrodeposition of Re-Ni alloys from ammoniacal citrate solution.

Abstract

Re-Ni alloys were electrodeposited from ammoniacal citrate baths. It was shown that both Re and Ni were considerably depolarized during simultaneous discharge of perrhenate and nickel ion, and that the maximum partial current efficiency of Re was consistently attained at an alloy composition of about 75wt. % Re. It was difficult to give a convincing explanation for these phenomena in terms of the bulk structure of the electrolytic solutions and deposited alloys or the hydrogen overpotential on the alloy.Further studies on the effect of perrhenate ion on Ni deposition suggested that the depolarization of Ni was caused by the catalytic action of the perrhenate ion adsorbed on the cathode.