Measuring the Repassivation Potential of Alloy 22 Using the Potentiodynamic-Galvanostatic-Potentiostatic Method

    Volume 4, Issue 9 (October 2007)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 26 October 2007

    Page Count: 16


    Evans, Kenneth J.

    Rebak, Raul B.
    Chemistry, Materials and Life Sciences Directorate, Lawrence Livermore National LaboratoryGE Global Research, LivermoreNiskayuna, CANY

    (Received 7 June 2007; accepted 14 September 2007)

    Abstract

    Traditionally, the susceptibility of Alloy 22 (N06022) to suffer crevice corrosion has been measured using the Cyclic Potentiodynamic Polarization (CPP) technique (ASTM G 61). When the alloy is not very susceptible to crevice corrosion, the values of repassivation potential obtained using the CPP technique are not highly reproducible. To circumvent the large uncertainty in the values of the repassivation potential by the CPP method, the repassivation potential of Alloy 22 may be measured using a slower method that combines sequentially potentiodynamic, galvanostatic, and potentiostatic treatments (this method is called the Tsujikawa-Hisamatsu Electrochemical or THE method). In the THE method the anodic charge is applied to the specimen in a more controlled manner, which avoids driving the alloy to transpassivity and therefore results in more reproducible repassivation potential values. Results using THE method under various testing conditions are presented. A new standard has been prepared for ASTM balloting for the THE method. The round robin matrix results are also discussed.


    Paper ID: JAI101230

    DOI: 10.1520/JAI101230

    ASTM International is a member of CrossRef.

    Author
    Title Measuring the Repassivation Potential of Alloy 22 Using the Potentiodynamic-Galvanostatic-Potentiostatic Method
    Symposium Advances in Electrochemical Techniques for Corrosion Monitoring and Measurement, 2007-05-23
    Committee G01