Comparison of some measuring techniques of corrosion currents with chronopotentiometry

Even though often considered as being elementary, the assessment of the corrosion rate of an electrochemical system such as iron/HCl 1 M appears extremely random. From one author to another and from one experimental technique to another, the results are widely variable. Our own experiments leading us to identical conclusions, we have undertaken an analysis of the classical electrochemical methods (mass loss measurement, tracing potentiokinetic polarization curves and impedance meters). It turns out that the main reason for the nonreproducibility and the disparity of results is related to the ageing of the electrode, which the classical methods amplify artificially. We then studied and proposed the use of galvanostatic chronopotentiometry, which gives a faithful, reliable and reproducible characterization.