The localized corrosion of Al 6XXX alloys

This paper presents some recent findings on localized corrosion with a focus on Al 6XXX alloys and on the current times resistance (IR) voltage that exists between the separated anodic and cathodic reactions. Some newly developed concepts help quantify the relationship between the IR voltage and the polarization curve that exists on the crevice wall, thereby providing for a deeper understanding on how crevice corrosion occurs in many metals and alloys. A signature of the IR voltage form of crevice corrosion in metal/electrolyte systems is the existence of an active/passive transition in their polarization curves. An aluminum/electrolyte system has been found to undergo this form of crevice corrosion. Some new results on intergranular corrosion in Al 6XXX alloy are also presented.