EVALUATION OF THE BEHAVIOR OF PARTICULATE POLYMERIC COATINGS IN A CORROSIVE ENVIRONMENT - INFLUENCE OF THE CONCENTRATION OF METAL PARTICLES

In this work pretreated steel specimens were coated by a spinning proc ess with particulate polymeric composites consisting of an epoxy resin (DOW 331) and iron powder. Applied coatings were roughly 70 mu m thic k and the contained quantity of iron particles was varied (7.5, 15, 30 % wt./wt.). The effect of the presence of iron particles in the coatin gs as well as the influence of their concentration on the evaluation o f the coatings' behaviour in a corrosive environment (3.58 NaCl) was s tudied. Electrochemical impedance spectroscopy, corrosion potential, c orrosion current density (Tafel) and dielectric measurements were perf ormed. Minor differences in the anticorrosive behaviour of the coating s were observed irrespective of the iron content in the coating. Effec tive resistance inhibition action of the composite coatings was dimini shed with the increase of exposure time to the corrosive environment b eing in all cases very close to that of the pure epoxy resin coatings.