Electrochemical interferometry of a carbon steel in 5–20 ppm KGR-134 inhibited seawater

Abstract

In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the number of the fringe evolutions during the corrosion test of a carbon steel in blank seawater and with seawater with different concentrations of a corrosion inhibitor. In other words, the anodic dissolution behaviors (corrosion) of the carbon steel were determined simultaneously by holographic interferometry, an electromagnetic method, and by the electrochemical impedance spectroscopy (EIS), an electronic method. So, the abrupt rate change in the number of the fringe evolutions during corrosion test, EIS, of the carbon steel is called electrochemical interferometry. The corrosion process of the steel samples was carried out in blank seawater and seawater with different concentrations, 5–20 ppm, of KGR-134 corrosion inhibitor using the EIS method, at room temperature. The electrochemical interferograms of the carbon steel in different solutions represent a detail picture of the rate change of the anodic dissolution of the steel throughout the corrosion processes. Furthermore, the optical interferometry data of the carbon steel were compared to the data which were obtained from the EIS tests. Consequently, holographic interferometry is found to be very useful as an electrochemical interferometer for monitoring the anodic dissolution behaviors of metals in aqueous solutions, in which the number of the fringe evolutions of the steel samples can be determined in situ.