New insights into the corrosion of magnesium alloys — The role of aluminum

The atmospheric corrosion of several Mg–Al alloys was investigated at − 4, 4 and 22 °C. The rate of corrosion increased with increasing temperature and decreasing Al content. Also, the effect of temperature became stronger with increasing Al content. The cast microstructure was found to influence both the average corrosion rate and the temperature dependence of corrosion. The influence of Al on corrosion and on the temperature dependence of corrosion is discussed in terms of the Al enriched layer in the bottom of the surface film and the breakdown of the same layer by chloride ions.