CORROSIN BEHAVIOR OF CFRP/CARBON STEEL SYSTEM IN A SIMULATED SOIL SOLUTION STUDIED BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

Electrochemical impedance spectroscopy (EIS) was employed to study the corrosion behaviour of the carbon fiber reinforced polymer (CFRP)/Carbon Steel system in a simulated soil solution.It was confirmed that the EIS could distinctly reflect the corrosion behaviour of this system.In the early time of immersion,the diffusion speed was less than the speed of the corrosion reaction at the interface and the EIS plots put up somewhat diffusion character.Then characteristic EIS plots with two undistinguishable loops were observed.In the middle and last part of the immersion period,the third time constant and a Warburg diffusion character appeared.Microscopic examination of the sample surface revealed that the alkaline medium was more destructive to the CFRP than the acidic medium.The alkaline medium led to a local corrosion on the surface of the carbon steel,but the acidic medium would result in a general corrosion.