STP1188

    The Effect of Parasitic Conduction Pathways on EIS Measurements in Low Conductivity Media

    Published: Jan 1993


      Format Pages Price  
    PDF Version (364K) 21 $25   ADD TO CART
    Complete Source PDF (7.3M) 21 $119   ADD TO CART


    Abstract

    Artifacts are ubiquitous to electrochemical impedance measurements at sufficiently high frequency. These artifacts, which are exacerbated by low conductivity solutions, can arise from the measurement electronics, the reference electrode, the electrical leads, or the electrochemical cell, or a combination thereof. This study has systematically examined the factors that may contribute to the occurrence of artifacts in low conductivity media. The frequency regime over which artifacts exist was identified for steel in lake water. The value and occurrence of the solution resistance was identified by adjusting the conductivity and comparing the results with calculated values. Possible contributions from the frequency response analyzer, potentiostat, reference electrode, and cell geometry were studied using a series of test resistors. The major contributors to artifacts appear to arise from the potentiostat and associated leads, and the ratio of the resistances between the working and reference and the reference and counter electrodes in the electrochemical cell. The problem of fitting complex spectra was approached by combining nodal analysis with simplex fitting. A model was determined that accurately reproduces the spectra for a set of current measuring resistors used in the voltage-drop configuration for two electrode measurements using a particular make of potentiostat.

    Keywords:

    impedance, artifacts, low conductivity, equivalent circuit, modeling


    Author Information:

    Stewart, KC
    Graduate research assistants, Center for Electrochemical Science and Engineering, University of Virginia, Charlottesville, VA

    Kolman, DG
    Graduate research assistants, Center for Electrochemical Science and Engineering, University of Virginia, Charlottesville, VA

    Taylor, SR
    Research assistant professor, Center for Electrochemical Science and Engineering, University of Virginia, Charlottesville, VA


    Paper ID: STP18064S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP18064S


    CrossRef ASTM International is a member of CrossRef.