Modeling of the electrochemical impedance spectroscopic behavior of passive iron using a genetic algorithm approach

Deconvolution of the Partial Anodic and Cathodic Processes during the Corrosion of Carbon Steel in Concrete Pore Solution under Simulated Anoxic Conditions

“…Detailed interpretation and derivation of Faradaic impedance Z f and impedance Z e,h in the latest PDM treating the passive film as a two-layer structure has been elaborated in Ref. [9], where linearization of the current response over small changes in applied potential (sinusoidal modulation) is employed as the approach to define the admittance and other parameters. To avoid repetition, only important formulae for calculating Z f are presented here: and…”

Exploration of the effect of chloride ion concentration and temperature on pitting corrosion of carbon steel in saturated Ca(OH) 2 solution

“…The goals of the present work are to: (1) study the localized corrosion behavior of carbon steel in saturated Ca(OH) 2 as a function of temperature, chloride ion concentration, and potential scan rate; (2) statistically analyze the relationship between the passivity breakdown potential versus chloride ion concentration and temperature in terms of the point defect model [9,[22][23][24][25][26][27], in order to extract the model parameters, and (3) Demonstrate that the PDM incorporating a normal distribution of the potential breakdown sites on the surface with respect to the diffusivity of cation vacancies in the barrier layer, adequately accounts for the experimentally observed distribution in the critical breakdown voltage.…”

pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

“…The adsorption of chloride ions into a passive film may increase the cation vacancy concentration in two possible ways: (1) Chlorides may enhance the transfer of metal ions from the oxide to the electrolyte; 62 (2) Chlorides may fill anion vacancies according to the point defect model (PDM). 29,30,33 As a consequence of mechanism (1), the concentration of surface cation vacancies increases in solutions containing chloride. The catalytically-enhanced transfer of cations from the oxide to the electrolyte leads to a new passive layer steady state.…”

“…This information can be obtained by electrochemical methods such as Electrochemical Impedance Spectroscopy (EIS) and Electrochemical Noise (EN). EIS has been used to investigate thin passive films for many years to extract useful parameters to characterize the structure of the passive film, and several models such as the Electrochemical Equivalent Circuit (EEC), 14,[25][26][27][28] point defect model (PDM) [29][30][31][32][33][34] and kinetic model 35,36 were developed. The latter two models have been more widely used recently; however, the EEC method is limited because the elements of the EEC have no specific physical meaning in some cases.…”