Influence of aging treatment on the pitting behavior associated with the dissolution of active nanoscale β-phase precipitates for an Al-Mg alloy

The pitting characteristics of Al-5 wt%Mg microelectrodes after various aging treatment have been investigated in a deaerated 0.6 M NaCl solution (pH 3.5). The dissolution current of single and numerous active β-phase precipitates have been detected on the aged alloys under anodic potentiostatic polarizations. The results show that the metastable pitting rates depend on the size and number of β-phase precipitates. The pitting potential decreases and the average size of β-phase increases initially with the increase of aging time, while for long-time aged alloys, the energy distribution plot (EDP) obtained from wavelet analysis technique can distinguish their small microstructural differences.