Electrochemical Research of the Failure Process about Three Epoxy Zinc Rich Primers in 3.5% NaCl Solution

Three commercial epoxy zinc rich primers were tested by electrochemical impedance spectroscopy (EIS) and experimental data were processed by ZSimpWin software. With SEM and fitted data, it is concluded that the pigment’s shape and size were the key factors that determined the coating’s performance, and the zinc powder’s cathodic protection and later barrier effect determined the failure time of coatings. The epoxy zinc rich primer B had the best performance compared with epoxy zinc rich primers A and C.