Abstract
Pitting growth mechanism in dilute chloride solution on clad aluminum alloys having potential slope was investigated by an electrochemical technique. The ability of pitting growth in the direction of thickness was determined by the relation between effects of positive potential slope by additional elements and of negative potential slope by concentration of Cl− at the pit bottom. In dilute chloride solution, pitting grew in the direction of thickness in spite of potential slope if it was gentle. Not only positive potential slope, but also potential defference of more than 90 mV between core alloy and sacrificial anode is required to protect core alloys for 7 days in tap water containing 1 ppm Cu2+.
