USE OF ELECTROCHEMICAL METHODS AS TOOLS FOR EVALUATING INTERFACE PARAMETERS IN HETEROGENEOUS SYSTEMS (METAL/AQUEOUS MEDIUM)

Abstract

When a metal surface comes into contact with an aqueous medium, a series of thermodynamic and kinetic processes begins, responsible for the formation of an electrochemical interface, which controls the oxidation/reduction processes related to the transfer of charge and mass in the vicinity of the metal. Considering the electrical characteristics of the interface, it is usually modeled by a series of passive elements (resistors and constant phase elements), whose magnitudes define both the thermodynamic and kinetic aspects of exchange reactions and/or charge and mass transfer. When this electrochemical interface is simulated with electrical elements, it is possible to apply the concepts of polarization to determine these interface parameters through the use of either stationary electric fields (DC) or electric fields that vary in time and frequency (AC). The type of polarization applied (both magnitude and signal type) defines a range of electrochemical techniques that allow for establishing, with a high degree of accuracy, the state of the interface. Comprehensive knowledge of all parameters of this interface is useful for determining the kinetics of material deterioration, the formation of passive and/or protective layers, the evaluation of the use of organic inhibitors as material deterioration inhibitors, etc. Despite the significant development of electrochemical techniques, coupled with the advancement of electronics and computers in the last two decades, it promises a hopeful future in potential new applications and/or combinations with other physical concepts, such as acoustic emission, etc.