Novel fast non-linear electrochemical impedance method for corrosion investigations

• Published in: Measurement : journal of the International Measurement Confederation 2021-03, Vol.173, p.108667, Article 108667
• Main Authors: Slepski, P., Szocinski, M., Lentka, G., Darowicki, K.
• Format: Article
• Language: English
• Subjects: Carbon; Carbon steel; Carbon steels; Charge transfer; Corrosion; Corrosion currents; Corrosion inhibitors; Corrosion rate; Corrosion resistance; Corrosion resistant steels; Electrochemical impedance spectroscopy; Electrode polarization; Electrodes; Impedance measurement; Impedance method; Inhibitors; Measurement; NLEIS; Perturbation
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2020.108667

•New nonlinear impedance method for monitoring of dynamic corrosion processes.•Perturbation with amplitude-modulated multi-frequency ac voltage signal.•Instantaneous corrosion current values obtained from 25 s time period. The paper presents a novel approach to corrosion rate monitoring using non-linear electrochemical impedance spectroscopy. The authors propose a new variant of non-linear impedance measurement using amplitude-modulated multi-frequency ac perturbation signal. It allows shortening of measurement duration so it is possible to monitor corrosion rate of the systems experiencing rapid changes. In this way a limitation resulting from lack of stationarity condition during the impedance measurements is overcome. Potentialities of the proposed method were presented on the example of carbon steel corrosion in 1 M HCl solution. Sudden changes in the corrosion rate were induced by injection of urotropine as a corrosion inhibitor. The investigations provided time-evolution of charge transfer resistance and corrosion current, clearly reflecting the changes occurring in the investigated system triggered by the inhibitor introduction. Obtained corrosion current values were in a good agreement with the ones acquired using classic method of polarization in the Tafel range.