STP1134

    A Comparison of Potentiodynamic Polarization Tests with Wet-Dry Mixed Salt-Spray Testing of Aluminum-Magnesium-Silicon Alloy

    Published: Jan 1992


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    Abstract

    Heat-treatable Al-Mg-Si alloy, in the form of all aluminum alloy conductor, (AAAC), has recently been introduced for overhead electrical supply in the United Kingdom. The material supplied to the industry in the United Kingdom may have differing corrosion resistance as a result of the different thermal histories of the alloy during manufacture. This paper presents data on the corrosion resistance of the aluminum alloy in a salt-spray test and compares this with the results of a potentiodynamic pitting test which has been proposed as a rapid assessment method for quality control of AAAC. Four batches of AAAC with differing thermal histories, were studied. The parameters measured include weight loss, loss in mechanical properties, and pitting data. The results indicated that the four alloys exhibit different corrosion characteristics in salt-spray accelerated corrosion tests. However, the potentiodynamic pitting test data failed to consistently rank the alloys in a discrete order. The data produced from both of the testing techniques are reviewed and contrasted. The results suggest that potentiodynamic tests are unable to characterize the atmospheric corrosion resistance of aluminum alloys. Thus, the adoption of such a test, as a quick screening technique, is not justifiable.

    Keywords:

    aluminum alloys, corrosion, accelerated tests, potentiodynamic pitting test, wet-dry mixed salt-spray tests


    Author Information:

    Baker, SV
    Research student and academic staff, Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester,

    Lyon, SB
    Research student and academic staff, Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester,

    Thompson, GE
    Research student and academic staff, Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester,

    Wood, GC
    Research student and academic staff, Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester,

    Lewis, KG
    Research manager, National Grid Co., Leatherhead, Surrey


    Paper ID: STP19579S

    Committee/Subcommittee: G01.04

    DOI: 10.1520/STP19579S


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