Corrosion resistance and dielectric properties of an iron oxide filled epoxy coating

Polymeric composites of a bisphenol-A-epoxy resin and iron oxide filler (15% w/w) were deposited on pretreated steel specimens. The applied coatings had a thickness of 80 mu m and 220 mu m. The modification of the anticorrosive and dielectric characteristics of these coatings, in a corrosive environment (3.5% NaCl), were monitored by potentiodynamic polarization measurements, electrochemical impedance spectroscopy, and dielectric measurements. Corrosion resistance of composite coatings was found to be somewhat higher than that of unfilled epoxy coatings. Coatings containing iron oxide exhibited capacitive behavior as revealed by dielectric and EIS measurements. This behavior is more pronounced in high thickness composite coatings.