EIS analysis of the electrochemical characteristics of the metal–water interface under the effect of temperature

The corrosion performance of metals is closely related to their durability. Available studies on metal corrosion have seldom focused on the interfacial reaction behaviour influenced by a conductive medium under different temperatures. In this work, a laboratory corrosion simulation environment has been designed for EIS measurements to investigate the electrochemical behaviour of copper immersed in distilled water in different temperature environments. The relationship between the mathematical model of impedance response and the equivalent circuit model is determined based on electrochemical kinetics theory. The complex process of the dielectric properties of distilled water affected by temperature is analysed, and a simple method for calculating the kinetic parameters is presented. The experimental and model results have a good fit, and the analysis results indicate that the semicircle in the high-frequency region of the complex impedance curve represents the charge transfer process of the conductive medium. The decrease in temperature is the major factor that inhibits the rate of dissolution and passivation, resulting in the change rate of surface coverage slowing down, until the attenuation of the mass transfer process of the conductive medium dominates the full range of AC frequencies. This model provides an improved approach for determining physical parameters based on electrochemical impedance spectroscopy to characterize the electrochemical properties of materials.