Time constraints in the testing of salt-fogged samples via electrochemical impedance spectroscopy

By Oliveira, C.G & Ferreira, M.G.S
Published in Progress in Organic Coatings NULL 2004

Abstract

Four types of commercial organic coil coatings, applied over galvanized and galvalumed steel, were evaluated by pre-wetting for 2–3 weeks and then drying for periods varying from 6 min to 1 week before the attachment of the O-ring style cell and addition of the test electrolyte for electrochemical testing via electrochemical impedance spectroscopy (EIS). The coil coatings were thin (25–50 μm) and the drying process was found to be relatively fast. The experiments confirmed the cyclic response of the EIS parameters from these organic coatings to be caused by the wetting and drying processes. In addition, the experiments allowed establishing the time constraints between removing a test specimen from a salt-fog chamber and re-exposure to a test electrolyte to minimize adversely affecting the status of the coating at the time of removal from the salt-fog chamber.

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