A study on the corrosion behavior of aluminum alloys in seawater

In this study, the aluminum alloys AA5083 and AA1100 were tested in seawater at 23 and 60 °C. Polarization plots showed that the alloys suffered from pitting attack. The breakdown potential of the two alloys decreased with an increase in test temperature with better corrosion resistance for alloy 1100. The weight loss tests revealed low corrosion rate values for both alloys, indicating a beneficial use for these alloys in marine environments. The pit morphology on the polarized aluminum alloys showed hemispherical isolated deeper pits on the 5083 alloy. Samples of the 1100 alloy revealed a higher number of shallow pits (more close to patches of general dissolution). The results showed that the type of intermetallic particles in the aluminum alloy played a major role in passivity breakdown and pit morphology in seawater.