Atmospheric-induced corrosion tests under MgCl 2 salt deposits were carried out on duplex stainless steel grade 2205 and 2507. As-received and 750°C heat-treated material conditions were investigated, and selected micro-structural sites targeted with salt-laden deposits to determine their corrosion response. Deposits were wetted under controlled climatic conditions at 80C and 40% relative humidity. Observations of micro-structural attack indicated the presence of net anodic and net cathodic sites. Ferrite was net anode with respect to austenite and hence more susceptible to atmospheric-induced corrosion in both as-received microstructures. Ferrite and ferrite/austenite interfaces were selectively attacked in heat-treated grade 2205, whereas mainly primary and secondary austenite in heat-treated grade 2507. Scanning Kelvin Probe Force Microscopy and Magnetic Force Microscopy were used to obtain high-resolution information about susceptible microstructure sites.