I've read about the pitting onset potential in polarization curve, other than that, is it true to contend that electrochemical techniques (such as impedance or polarization) are just limited to study of uniform corrosion? When the corrosion scale formed on the metal is uniform, it's rational to anticipate a protective behavior against further corrosion as a function of time and in research papers this protectiveness is seen a lot. But what makes trouble in real systems with larger bodies of exposed metals is the localized corrosion. How can I study this localized corrosion as a function of time with electrochemical techniques?