“…Scanning vibrating electrode techniques (SVET) measures the local currents, which can be helpful to characterize defects in coating but cannot overcome the inherent difficulty in measuring currents underneath high resistance coatings [31,32]. Local electrochemical impedance spectroscopy and mapping (LEIS and LEIM) [33,34,35,36,37,38] are becoming widespread techniques to study buried interfaces for the systems in which the polymer does not have initial defects [39,40,41]. SVET and LEIS measure both the local current density, for the former case, the DC component is measured, whereas for the later, the AC component at a selected frequency can be obtained.…”