Effect of potassium cyanide on kinetics of zinc electroplating from tetrahydroxozincate solutions

By the method of chronopotentiometry, it is shown that, being added to tetrahydroxozincate baths, potassium cyanide affects the kinetic parameters of zinc electroplating, by increasing the slope of Tafel plot, decreasing the cathodic transfer coefficient, and reducing the exchange current. The effect strengthens with a decrease in zinc concentration in the bath; the limiting current of zinc deposition loses its diffusion nature. The results reveal the decisive effect of CN- ions on the composition and properties of interface layers formed at a zinc cathode during the electrolysis.