Cobalt dissolution in a carbonate/bicarbonate media was studied in order to elucidate the kinetic of the
metal corrosion processes. Steady-state polarization and electrochemical impedance measurements were
carried out during the active metal dissolution at different electrode rotation speeds. A reaction mechanism
is presented in order to explain the metal dissolution: cobalt electrodissolution starts with the formation
of intermediate (CoHCO3)ads on the electrode surface, followed by the simultaneous formation of
a CoðCO3Þ2 2 complex and the formation of a CoO film. Mass transport is characterised by diffusion of the
CoðCO3Þ2 2 complex away from the electrode. The reaction model was validated by an accurate simulation
of the experimental steady-state polarisation and impedance measurements. |
