Corrosion behaviours of carbon steel coated with polyester and polyvinylester in a simulated flue gas desulphurisation (FGD) fluid (i.e., a mixture of H2SO4 and 0.1 wt% Fe-2(SO4)(3) at pH=2) have been investigated with electrochemical impedance spectroscopy (EIS). The protective nature of the coatings at 25 degrees C has been observed in the following order: polyvinylester primer >> polyvinylester topcoat > polyester topcoat > polyester primer. Coating deterioration occurred and the coating deterioration rate accelerated with increasing temperatures upto 85 degrees C. However, the corrosion resistance sequence has remained the same. Equivalent circuits are suggested for various coatings to discuss their mechanisms in this work.
