The influence of talc particles on corrosion protecting properties of polyurethane coating on carbon steel in 3.5 % NaCl solution

In this study, the main concern is investigating the effect of talc on the protecting properties of polyurethane (PU) coating based on acrylic polyol/hexamethylene diisocyanate. To this end, PU coatings containing different concentrations of talc (0, 5, 10 and 15 %), were prepared and applied to the steel surface. Anticorrosion behavior of the coatings was evaluated by electrochemical impedance spectroscopy (EIS) during 90 days of immersion in 3.5 % NaCl. The EIS data were used to simulate the anticorrosion behavior of the coatings by using equivalent circuit models (ECMs). The obtained results showed the highly positive effect of talc and the best protective performance was obtained at 10 % by weight of talc concentration. Moreover, different complementary tests, including the surface study by scanning electron microscopy (SEM) and atomic force microscopy (AFM), wettability by contact angle and the coating adhesion by pull-off test were employed to satisfy the EIS data and further study the protecting behavior of PU coating, modified with talc particles.