Crevice corrosion behaviour of superaustenitic stainless steels: Dynamic electrochemical impedance spectroscopy and atomic force microscopy studies

Potentiodynamic anodic polarisation and dynamic electrochemical impedance spectroscopic (DEIS) measurements were carried out for 316L SS, alloy 33 and alloy 24 in natural sea water in order to assess their crevice corrosion resistance. DEIS measurements were performed from open circuit potential to dissolution potential. It was shown that the impedance measurements in potentiodynamic conditions allow simultaneous investigation of changes in passive layer structure. The impedance spectra of various potential regions were also discussed. The surface morphology of the alloys after crevice corrosion studies were studied using optical microscope and atomic force microscopy (AFM).