STP1194

    Prediction of Localized Corrosion Using Modeling and Experimental Techniques

    Published: Jan 1994


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    Abstract

    An overall approach to life prediction of a component undergoing localized corrosion involving initiation and repassivation is considered. A crevice corrosion initiation model for Fe-Ni-Cr-Mo alloys is presented in this paper. This is a finite difference model that considers the combined effects of hydrolysis and transport in predicting the evolution of the solution chemistry inside a crevice of a given geometry. Crevice corrosion initiation time is computed by equating the time it takes for the crevice-solution chemistry to evolve to a critical solution chemistry for the depassivation of a given alloy. Depassivation pH is measured on non-creviced (open) samples as a function of environmental factors such as temperature, chloride, and sulfate. The measured depassivation pH is then used as an input variable in the crevice corrosion model to calculate the initiation time. The use of crevice corrosion repassivation potential as a bounding parameter for performance prediction is also examined. The limitations of the current models and future directions are identified.

    Keywords:

    Crevice, pitting, corrosion, model, repassivation, depassivation, pH, chloride, stainless steel, alloy 825


    Author Information:

    Sridhar, N
    Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute, San Antonio, TX

    Cragnolino, GA
    Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute, San Antonio, TX

    Walton, JC
    Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute, San Antonio, TX

    Dunn, D
    Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute, San Antonio, TX


    Paper ID: STP24884S

    Committee/Subcommittee: G01.08

    DOI: 10.1520/STP24884S


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