The kinetics of nickel passivation in sulfuric acid, and the effects of plastic deformation on the kinetics of various electrochemical reactions on nickel

Abstract

The kinetics of passivation in sulfuric acid of undeformed nickel have been measured by the rotating cyclinder technique at various IR-drop-compensated applied potentials. The passivation efficiency as a function of passivation time has been measured by the rotating ring-disc technique. These results are compared with those obtained on continuously scratched, rotating cylindrical electrodes at passivating potentials, supplemented by measurements at active anodic, and cathodic potentials. It is found that plastic deformation of nickel much enhances the cathodic reduction of hydrogen ion and the anodic dissolution of nickel, but impedes the passivation of nickel and reduces the passivation efficiency. Furthermore, the deformation-produced surface features responsible for these differences have a limited duration controlled by surface diffusion in the cathodic range, and by surface diffusion and preferential dissolution in the anodic range.