Stripping voltammetry of nanoscale films of Zn–Ni alloy

Abstract

Nanoscale Zn–Ni alloy films of ~ 20…90 nm thickness were obtained from ammonia-glycinate electrolyte in the potential range from − 1.15 to − 1.475 V. Chemical and phase composition of films were analyzed by stripping voltammetry in alkaline ammonia-glycinate electrolyte. It is shown that the method of stripping-voltammetry in this electrolyte allows estimation of the content of both crystalline and amorphous phases of Zn–Ni alloy, including films with small content of components. All alloy films contain a γ-phase in the mentioned range of potentials. Its maximum content (95%) is observed at a potential of − 1.2 V corresponding to the beginning of the limiting current on the polarization curve of the alloy deposition. Despite the fact that Zn is a more negative metal in the zinc–nickel pair, its content in the alloy decreases with an increase in the polarization of deposition due to anomalous codeposition of Zn with Ni. As the Ni content increases, the contributions of the β-phase and the Ni-phase increase. It is shown that in an electrolyte of the same composition, layers of an alloy of different chemical and phase composition are deposited depending on the potential. Results can be useful both for analyzing the composition of films obtained from other electrolytes, and for choosing the architecture of multilayer coatings deposited by the single-bath method.