STP1277: Electrochemical Noise Measurements During Exfoliation of Aluminum Alloys

    de Damborenea, J
    Senior Research, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avenida de Gregorio del Amo, Madrid,

    Fernández, B
    Senior Research, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avenida de Gregorio del Amo, Madrid,

    Pages: 13    Published: Jan 1996


    Abstract

    Electrochemical noise measurements (ENMs) have been carried out during exfoliation corrosion of an aluminum-lithium alloy (8090) in the EXCO (ASTM Test Method for Exfoliation Corrosion Susceptibility in 2XXX and 7XXX Series Aluminum Alloys [EXCO Test] [G 34]) test solution. By means of the maximum entropy method (MEM), the potential and current fluctuations were converted into power spectral density (PSD) plots to study the specific variables related to electrochemical noise (low frequency amplitude, slopes). Noise resistance obtained from the standard deviation of potential and current was compared with the charge transference resistance (Rct) from electrochemical impedance spectroscopy (EIS) measurements. The results show that ENM can be used to detect early stages in localized corrosion. However, when the solution is very aggressive, indications of localized corrosion can be masked by uniform corrosion.

    Keywords:

    electrochemical noise measurement, intergranular corrosion, exfoliation corrosion, EXCO test, aluminum-lithium alloy, electrochemical impedance spectroscopy


    Paper ID: STP37973S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP37973S


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