EIS studies of the destruction behavior of a corrosion inhibitor film on carbon steel surface under hydrodynamic conditions

Abstract

Effect of surface water shear stress on the performance of an inhibitor film used in the carbon steel pipelines for oil and gas product transportation is studied. Experiments were conducted in laboratory by electrochemical impedance spectroscopy (EIS). EIS that was carried out under various rotation rates, different temperature, and immersion time was taken to investigate the behavior of a corrosion inhibitor and the destruction process. Typical EIS spectral changes were acquired during the film destruction processes, and this means that EIS is an effective method for evaluating inhibitor performance and monitoring the film layers’ behavior. Experimental results show that the film layers become more porous with increase in rotation rates and temperature. Therefore, the performance of this corrosion inhibitor decreased resulting from surface shear stress and bubble impact. In addition, scanning electron microscopy (SEM) was also taken to help confirm the inhibitor film structure under different conditions.