The electrodissolution process of polycrystalline cobalt in carbonate-bicarbonate buffers covering relatively wide ranges of ionic strength, pH, and the hydrodynamic condition of the electrolyte solution, was investigated using electrochemical impedance spectroscopy (EIS). Impedance spectra were analyzed to determine the dynamic behavior of the system by the application of transfer function analysis using non-linear fitting routines according to a model which gives information about the characteristic parameters of the electrochemical process at the reaction interface. Data analysis using non-linear fitting routines showed that the impedance spectra of the cobalt electrodissolution process in carbonate-bicarbonate buffers at pH 8.9-10.5 can be modeled considering a finite-length Warburg impedance that accounts for the mass transport process taking place in the electrolyte.
finite-length Warburg impedance; cobalt dissolution; carbonate-bicarbonate solutions
