EVALUATION OF CORROSION BEHAVIOR OF METAL-FILLED POLYMERIC COATINGS

Pretreated steel samples have been coated with a layer (similar to 250 mu m) of a metal-filled (Ni, Cu, Fe) epoxy resin (Dow 324) deposited by a spinning process. The corrosion behavior of these specimens in 3. 5% NaCI has been investigated by electrochemical impedance spectroscop y, Tafel measurements, and dielectric measurements undertaken in the f requency range of 20-10(7) Hz. Correlation between the different appro aches shows that coatings of epoxy resin composites filled with iron p owder possessing higher ac resistance and lower capacitance are more p rotective than the pure epoxy resin coatings. On the contrary, copper or nickel powder addition leads to coatings which, though still protec tive, exhibit lower protection than the pure epoxy.