Amperometric and potentiometric probes were employed for the detection and characterization
of reactive sites on the 2098-T351 Al-alloy (AA2098-T351) using scanning electrochemical
microscopy (SECM). Firstly, the probe of concept was performed on a model Mg-Al galvanic pair
system using SECM in the amperometric and potentiometric operation modes, in order to address
the responsiveness of the probes for the characterization of this galvanic pair system. Next, these
sensing probes were employed to characterize the 2098-T351 alloy surface immersed in a saline
aqueous solution at ambient temperature. The distribution of reactive sites and the local pH changes
associated with severe localized corrosion (SLC) on the alloy surface were imaged and subsequently
studied. Higher hydrogen evolution, lower oxygen depletion and acidification occurred at the SLC
sites developed on the 2098-T351 Al-alloy
