Point defect model for passivity breakdown on hyper-duplex stainless steel 2707 in solutions containing bromide at different temperatures

Evaluation of the Pitting Corrosion of Modified Martensitic Stainless Steel in CO2 Environment Using Point Defect Model

“…) and for the absorption of the anions into oxygen vacancies at the film/solution interface, respectively [37]. J m is the annihilation rate of cation vacancies at the metal/film interface.…”

“…The parameters α and β are the dependencies of the potential drop through the film/solution interface (φ f/s ) on the applied potential V and pH, respectively. φ 0 f /s is the value of φ f/s in the standard state of V = 0, R is the gas constant, T is the temperature, pH = 0, N v is Avogadro's number, F is Faraday's constant, and w describes the energy related to the absorption of Cl ions [37,38].…”

“…It is worth mentioning that the pitting potential significantly shifted to the more negative values and narrowed the stable passive range at higher concentrations of NaCl due to the growth of the current in the stable passivity, which somewhat decreased the protection effectiveness. The value of the cation annihilation rate at the bl/MMSS interface (j m ) was estimated by employing the following formula [37]:…”

Mixed potential model for passivity characters of hyper-duplex stainless steel 2707 in ammonium carbonate solution containing chloride

“…Literature reviews indicate that the protectiveness of the passive film and its breakdown are critical aspects of pitting corrosion [12][13][14][15]. Previously, we have interpreted the pitting parameters of HDSS 2707 in terms of the Point Defect Model (PDM) [16], whereas the other key corrosion factors, including the effect of temperature and applied potential on the oxide film properties, such as the defect concentration, the defect type, the dissolution current density, the corrosion rate (µm/year), and the growth rate of the passive film formed on HDSS 2707 surface are still unknown.…”

“…The interplay of the dynamical properties of the passive film formed on the metal surface can be described by the process of point defect reactions, such as the rate constants (k i ), the standard rate constants (k 0 i ), the transfer coefficients (α i ), the diffusion coefficient (D), J m , and J ca at the m/bl interface [27,28]. These kinetic parameters can be determined by optimizing the PDM on electrochemical impedance spectroscopic (EIS) data [29], and some of them have been incorporated into our previous research related to pitting of HDSS 2707 [16].…”