STP1232: Electrochemical Techniques for Detection of Localized Corrosion Phenomena

    Mansfeld, F
    Professor and Ph.D. candidate, University of Southern California, Los Angeles, CA

    Xiao, H
    Professor and Ph.D. candidate, University of Southern California, Los Angeles, CA

    Pages: 19    Published: Jan 1994


    Abstract

    Most corrosion reactions in microbiologically influenced corrosion (MIC) are of localized nature. It is therefore necessary to develop methods that can provide information concerning the corrosion reactions occurring under biofilms. Electrochemical techniques such as electrochemical impedance spectroscopy (EIS), electrochemical noise analysis (ENA), and measurements of pit propagation rates for thin metal foils have been evaluated as tools for the study of localized corrosion in MIC. Initial studies have been carried out in abiotic NaCl solutions. Software has been prepared for collection and analysis of electrochemical noise data. It has been found that use of potential noise alone can lead to erroneous conclusions concerning the occurrence of pitting for Al alloys and the inhibition of corrosion of iron. However, current noise seems to be directly related to the extent of pitting. EIS has been used to detect the initiation and propagation of localized corrosion and to confirm the conclusions reached for the ENA-data. For iron in NaCl, the noise resistance had similar values as the polarization resistance determined by EIS. In thin foil tests, penetration of Al and nickel foils has been measured during exposure to 0.5 N NaCl.

    Keywords:

    impedance spectroscopy, electrochemical noise, pit propagation, iron, aluminum, polarization resistance, localized corrosion


    Paper ID: STP12924S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP12924S


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