STP1056: IR Drop in Electrochemical Corrosion Studies— Part I: Basic Concepts and Estimates of Possible Measurement Errors

    Ehrhardt, WC
    Senior research scientist, Betz Laboratories, Inc., Trevose, PA

    Pages: 32    Published: Jan 1990


    Abstract

    Electrochemical techniques used in the study of corrosion are particularly susceptible to errors due to IR drop when used to study systems such as the corrosion of steel in natural waters. The influence of the electrochemical measurement cell geometry on both the nature and the magnitude of the expected errors is reviewed. Also, the effect of a non uniform current distribution on the working electrode is examined. Expected errors for a range of corrosion rates and water conductivities that are typical of steel in cooling systems are presented for three types of experiments. These experiments are: simple linear polarization (polarization resistance), small range polarization, which is computer-fit to extract the corrosion rate and Tafel parameters, and full polarization.

    Keywords:

    cell constant, corrosion, corrosion probe, curve fitting, current distribution, electrochemical cell, IR compensation, polarization resistance, solution resistance, steels, Tafel slopes


    Paper ID: STP25280S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP25280S


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