Abstract: The electrochemical studies on corroding metallic electrodes carried out in the State Key Laberatory for Corrosion and Protection are reviewed briefly: (1) General equations of faradaic admittance under potential-control condition were derived based on the stabillity conditions of steady processes. The faradaic admittance at mixed potential then was deduced based on these equations and the electrochemical impedance spectroscopy (EIS) at corrosion potentials in the solutions containing interface inhibitors was diseussed by application of the thecetical results obtained. (2) The spectral power density (SPD) curves for electrochemical noise (EN) during the initial stagu of pitting corrosion were observed for iron and stainless steels in various solutions. In all the svstems studied, the EN is "white" noise at very low frequencies and is f-n noise in higher frequency range. The value of n is within the range from 2 to 4. An equation for the SPD of the EN was derived and the observed phenomena were well elucidated.

Key words: Electreehemical impedance spectroscopy, Faradaic admittance, Electrochemical noise, Inhibitor, Pitting corrosion