ON THE KINETIC MECHANISM OF ZINC ELECTRODEPOSITION IN THE REGION OF NEGATIVE POLARIZATION RESISTANCE

We found that the autocatalytic mechanism proposed by Epelboin et al.1 to explain the negative resistance observed during the electrodeposition of zinc is inconsistent, as it neglects to account for the vacant sites in the mass-action kinetics. Their mechanism results in a quartic equation rather than a cubic equation and cannot explain the observed S-shaped polarization where three steady states can occur. We propose a simple mechanism for metal electrodeposition which can admit a three-root multiplicity, in agreement with experimental observations.