APPLICATION OF MEASUREMENT MODELS FOR ANALYSIS OF IMPEDANCE SPECTRA

Measurement models have been applied to electrochemical impedance data collected at the corrosion potential for a copper disk rotating in alkaline- and acid-aerated 0.5 M chloride solutions. Several applications of measurement models for the interpretation of experimental impedance data are demonstrated. Corrosion is a nonstationary process, and nonstationary behavior associated with corrosion frequently influences impedance data. If data can be shown to be consistent with the Kramers-Kronig relations, nonstationary influences can be neglected. Measurement models provide a quantitative method for identifying the portion of an impedance spectrum that is consistent with the Kramers-Kronig relations and, therefore, can be interpreted in terms of pseudo-steady-state models. Measurement models also provide a very sensitive means of interpreting impedance spectra in terms of the effects of physical parameters, such as immersion time and disk rotation speed.