Synthesis, Corrosion and Electrocatalytic Properties of Tin-Cobalt Alloy Coatings

Tin-cobalt alloy coatings with a tin content of 5–85 wt.% were synthesized from a poly­ligand citrate-chloride electrolyte. The surface morphology and composition of tin-cobalt alloy coatings depending on the conditions of their production were studied using EDS and XRD methods. The dynamics of changes in the parameters of the equivalent impedance circuit on tin-cobalt alloy coatings in 0.1 mol∙l-1 KOH solution is determined by the process of formation of a cobalt (II) hydroxide layer on the coating surface. The parameters of corrosion resistance and electrocatalytic activity of the coatings in the reaction of hydrogen evolution were calculated from the stationary voltammetry dependences. The corrosion currents on tin-cobalt alloy coatings with a tin content of 33–85 wt.% are about 10-6–10-8 A∙cm-2. An inverse dependence of the hydrogen evolution overvoltage on tin-cobalt alloy coatings on the corrosion current was established.