A NOVEL WAY OF MEASURING LOCAL ELECTROCHEMICAL IMPEDANCE USING A SINGLE VIBRATING PROBE

A novel method of measuring local electrochemical impedance using a si ngle vibrating probe electrode has been developed by modification of a commercial device of scanning vibrating electrode technique (SVET). T he small size of the vibrating probe used by the SVET minimizes the sc reening effect of the probe on the distribution of current in the regi on of analysis. Furthermore, the local impedance as defined here takes into account not only the local current density but also the local el ectrode potential, as opposed to the measurements proposed up to now i n the literature. The signal processing used to obtain this impedance is explained in detail and tested on a dummy cell including a phototra nsistor to simulate a vibrating electrode. The local impedance of an e lectrode simulating pitting corrosion is also measured with this syste m.