Corrosion performance of powder coated aluminium using EIS

Electrochemical impedance spectroscopy (EIS) studies have been carried out to characterise powder coated aluminium substrates with different initial surface pretreatments. Water permeation of the epoxy/polyester powder coated samples was evaluated using capacitance methods. The impedance spectra were interpreted in terms of the movement of water into the coating and/or to the coating/metal interface. The water uptake measurements revealed that pretreatments did not considerably affect the properties of the coatings during the water permeation stage, although their influence on overall performance was significant. (C) 2003 Published by Elsevier Science B.V.