Evaluation of passive film behaviour of super austenitic stainless steels at different potential regions using dynamic electrochemical impedance spectroscopy
ABSTRACT Potentiodynamic anodic polarisation and dynamic electrochemical impedance spectroscopic (DEIS) measurements were carried out
on 316L stainless steel and alloys 926 and 31 in natural seawater in order to assess the crevice corrosion resistance. DEIS
measurements were performed over a wide range of potentials covering the corrosion potential, passive region, breakdown region
and dissolution region. The impedance measurements in potentiodynamic conditions clearly reveal the changes that occur in
the passive layer with change in potential. The impedance spectra at different potential regions were also discussed elaborately.
The surface morphology of the alloy after crevice corrosion was studied using optical microscope and atomic force microscopy.
KeywordsStainless steel-Crevice corrosion-Dynamic electrochemical impedance spectroscopy-Atomic force microscopy
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ABSTRACT: Theoretical principles for determination of instantaneous impedance spectra were formulated. Coupling of the pseudo-white noise and short-time Fourier transformation methods allows determination of impedance spectra changes as the function of time. The theoretical principles of the new measurement method indicate the possibility of conducting impedance investigations of non-stationary processes. The frequency resolution and time selection of the total time–frequency analysis of impedance spectra depend on the choice of the size of the Gaussian window.Journal of Electroanalytical Chemistry 05/2000; · 2.58 Impact Factor
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ABSTRACT: Passive layers formed electrochemically at constant potentials are studied by impedance spectroscopy in 1 M KOH. In the high frequency range, they act as a cpe. Passive layers change with potential and at lower frequencies, adsorption or insertion reactions are observed in several potential ranges. Passive layers have over a limited potential range, p-semiconductive properties that depend on their preparation conditions (time, potential): the number of acceptors decreases with the formation time, and the flat band potential Efb decreases when the formation potential increases. Due to the shift of kinetical processes towards high frequencies in some potential ranges, the frequency dispersion in the high frequency range varies with potential, leading to an apparent variation of the Edb values deduced from the Mott-Schottky plots.Electrochimica Acta 08/1996; 41(17):2761-2771. · 4.09 Impact Factor
- Journal of The Electrochemical Society - J ELECTROCHEM SOC. 01/1993; 140(5).