EIS ANALYSIS OF FLUGRGCARBGN ANTICORROSION COATING AFTER ARTIFICIALLY ACCELERATED AGING

摘要

With the aid of a xenon lamp, artificially accelerated aging test is carried out to evaluate the aging behavior of fluorocarbon coating/carbon steel system. The aged coatings were characterized with Fourier Transform Infra Red (FTIR) spectrometry, an optical microscope and studied by Electrochemical Impedance spectrum (EIS), to evaluate the properties of the aged coatings. The results show that for coatings with different aging periods after immersion during the same time, the resistance of the coatings is getting lower with the increase of the aging time, while the capacitance and the soakage is getting larger with the increase of the aging time. It shows that the early aging of the coatings influences its protective properties towards the corrosion medium. The reason is that the amide bonds of the coating are broken after exposure to the photo-radiation. Furthermore, the roughness of the surface increases and the gloss decreases with the increase of the aging time. The properties of coating after aging change its electrochemical properties and its electrochemical behavior. The changes of the surface state and of the chemical structure of the aged coating accelerate the penetration of medium into the coatings and therefore accelerate the corrosion of metal occurs under the coating.