Effects of deposited salts on corrosion behavior for 1100 aluminum alloy during constant dew point test

Abstract

Effects of deposited salts on corrosion behavior for an 1100 aluminum alloy were investigated by a constant dew point test with NaCl, MgCl2, and CaCl2. In the constant dew point test, corrosion depth of the 1100 aluminum alloy depended on the deposited salts, increasing in the order of MgCl2, CaCl2, and NaCl. On the other hands, in an immersion test, corrosion depth was independent of the cation species in relatively dilute solutions but depended in concentrated solutions. Furthermore, in a polarization measurement, a cathodic reaction strongly depended on the cation species in the concentrated solutions. It is suggested that the deposited salts in the atmospheric corrosion affect not only the time of wetness but also the cathodic reaction around deliquescence relative humidity where concentrated solutions are formed.