Effects of environmental factors on atmospheric corrosion of aluminium and its alloys under constant dew point conditions

Environmental factors, such as chloride deposition rate, dew point and the addition of sulphate ions, were investigated under constant dew point conditions. Corrosion mass losses of AA1100 increased with increasing chloride deposition rates, dew points and with the absence of sulphate ions. Sulphate ions were shown to have an inhibition effect on pitting corrosion of aluminium alloys. High-purity aluminium was not sensitive to an increase of chloride deposition or dew point. As dew point increased from 5 to 28 °C, the corrosion mass loss of AA6061 decreased. The pitting susceptibility of AA6061 was rather high under low dew point conditions.

► The presence of sulphate ions inhibited the initiation of pitting corrosion.
► Corrosion mass loss of AA1100 increases with dew points and Cl− deposition rates.
► Corrosion mass loss of AA6061 changes reversely with dew points.
► Pitting susceptibility of AA6061 is rather high under low dew point conditions.