Diffusivity of point defects in the passive film on Fe

Diffusivity of point defects (D0) in the passive film formed on Fe in deaerated pH 8.5 buffer solution at ambient temperature was estimated by the Mott-Schottky analysis based on the Point Defect Model and surface charge approach assuming that donors are oxygen vacancies and/or iron interstitials. From the exponential decay of the concentration of donors with film formation potential, D0 was calculated to be 1.69 × 10−20 cm2 s−1.