Electrodepositing Zn-Ni alloys from alkaline electrolytes

Codeposition of zinc and nickel from zincate electrolytes containing amino acid and alkanolamine is studied. The alloy composition is constant in a wide range of current densities i. The relationship [c(Ni)/c(Zn)](alloy) greater than or equal to [c(Ni(II))/c(Zn(II))](sol) is valid for all i, pointing to normal codeposition of alloy components. In addition to traditional limiting diffusion currents, partial voltammograms for Zn and Ni contain diffusion-kinetic waves caused by a concurrent hydrogen evolution. At an increase in the Ni concentration, the throwing power and uniformity of the alloying-component distribution along the Mohller cell cathode slightly decrease but remain sufficiently high, which is of great importance for industrial electroplating.