SYMPOSIA PAPER Published: 01 January 1992
STP19579S

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

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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.

Author Information

Baker, SV
Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester, United Kingdom
Lyon, SB
Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester, United Kingdom
Thompson, GE
Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester, United Kingdom
Wood, GC
Corrosion and Protection Centre, University of Manchester Institute of Science and Technology, Manchester, United Kingdom
Lewis, KG
National Grid Co., Leatherhead, Surrey, United Kingdom
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Details
Developed by Committee: G01
Pages: 32–49
DOI: 10.1520/STP19579S
ISBN-EB: 978-0-8031-5195-6
ISBN-13: 978-0-8031-1435-7