In Fig. 6 distribution of depth of pits measured by topography is given for the anodized specimens. Here we can observe that size of the largest pit observed has been increased as compared to the pits observed for pickled specimens which can be explained by the complete dissolution of constituent particles. In a recent investigation for aluminium alloy 7075, Savas and Earthman [18] studied the effects of different anodizing pretreatment solutions on localized corrosion behaviour. They hypothesized that if pits, initiated during pretreatment solution exposure, were beyond a threshold size (10–20 μm), a higher current density existed at these locations during anodizing process, thus resulting in deeper pit structure. During this study, the maximum pit depth was determined to be 12 μm by topography measurements for anodized specimens.