STP1188: Corrosion Prediction from Circuit Models Application to Evaluation of Corrosion Inhibitors

    Silverman, DC
    Fellow, Monsanto Company, St. Louis, MO

    Pages: 13    Published: Jan 1993


    Abstract

    Detailed kinetic models are not often available to predict the efficacy of inhibitors of iron corrosion in water at near neutral pH from electrochemical impedance spectra. Circuit models offer a way of using the spectra to estimate corrosion and of making practical conclusions about the mechanism in the absence of kinetic models. Circuit elements estimated from regression of the models against the impedance spectra are shown to provide information for the estimation of corrosion rates and for insights into corrosion behavior. However, simultaneous agreement between calculated and measured impedance spectra, and between predicted and measured corrosion rates, does not necessarily mean that the circuit model is a unique representation of the spectra. Results are presented that show that similar values of the circuit elements can be obtained from regression of two different models against the measured spectra.

    Keywords:

    electrochemical impedance spectroscopy (EIS), polarization resistance, corrosion, modeling, inhibitor, iron, steel, amino-trimethyl phosphonic acid (ATMP), circuit models, corrosion rate, velocity, rotating cylinder electrode


    Paper ID: STP18070S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP18070S


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