Effect of potassium cyanide on electrodeposition of zinc from zincate solutions

With the use of cyclic voltammetry, chronopotentiometry, and a rotating disk electrode, potassium cyanide introduced into tetrahydroxozincate solution is shown to inhibit the process and decrease the limiting current of zinc electrodeposition. An increase in the concentration of cyanide ions in the solution enhances the effect. The impediment to the cathodic process by cyanide is not of a diffusion nature and considerably disturbs the diffusion character of the limiting current. During the aging the zincate solution containing cyanide ions, the deposition kinetics and the quality of zincate deposits change. All results considered, make us conclude that the function of cyanide ions is not to form electroinactive zinc complexes, but to change the properties of scarcely soluble compounds formed on the cathode's interface in the course of electrolysis.