Influence of coating thickness on the barrier effect of marine paint binders: An assessment using impedance measurements

A.R. DI SARLI; C.I. ELSNER

Journal Chemical Technology and Biotechnology

John Willey & Sons

Año: 1992 vol. 55 p. 285 - 292

1097-4660

The influence of coating thickness on the barrier effect afforded for several paint binders, as a part of naval steel/organic coating/artificial sea water systems, by using electrochemical impedance spectroscopy and corrosion potential measurements was studied. As a function of the immersion time, ionic resistance and dielectric capacitance for the membrane were determined employing non-linear fit routines on the experimental impedance spectra. Simultaneously corrosion potential values for the substrate were measured. These results showed that most of the samples exhibited very good dielectric and barrier properties whilst they remained in contact with the electrolyte and that the corrosion potential changes were in agreement with those of the impedance spectra. The importance of producing coatings with both uniform chemical composition and the thickness to avoid localized corrosion was emphasized.