INFLUENCE OF THE PIGMENT SHAPE ON THE ELECTROCHEMICAL BEHAVIORS OF ZINC-RICH PAINT COATINGS IN 3.5% NaCl SOLUTION
Influence of the Pigment Shape on the Electrochemical Behaviors of Zinc—Rich Paint Coatings in 3.5% NaCl Solution

Electrochemical impedance spectroscopy (EIS) was used to study the influences of the binder, pigment shape and the coating thickness on the corrosion prevention performance of the zinc-rich coatings (ZRC). There are two time constants for these coatings, the first one is attributed to the contact impedances between the different zinc particles and the second one is related to the charge transfer resistance of the Zn dissolution process. Furthermore, the EIS data of ZRC were interpreted according to equivalent circuit models. The corresponding parameters were derived to assess the coating deterioration with time and the performance between zinc dust primers and zinc flake primers were compared. The results showed that the zinc flake reduced the cathodic protection period of the ZRC and rapidly produced a little compact barrier.