Influence of chloride ion concentration and temperature on the corrosion of Mg–Al alloys in salt fog

The influence of temperature and chloride concentration on the corrosion behaviour of Mg–Al alloys exposed to salt fog was evaluated. Corrosion attack increased with decreasing aluminium content in the alloy and increasing Cl− concentration and temperature. The effect of Al–Mn inclusions, which revealed several stoichiometries and were up to 300 mV more noble than the magnesium matrix, was only noticeable in the early stages of corrosion of the AZ31 alloy. Aluminium segregation and β-phase distribution were the main controlling factors for the AZ80 and AZ91D alloys, the latter being more susceptible to variations in the saline concentration.