Corrosion behavior of lacquered tinplate cans in contact with cockles (cardium edulis) in brine solution

Abstract Tinplate cans internally coated with an epoxyphenolic plus zinc oxide (ZnO) lacquer were studied. The relationship between lacquer adhesion and total chromium, metallic chromium, and chromium oxide (CrOx) in the passivated layer was analyzed. The thickness of the CrOx layer is a controlling parameter of adhesion. Electrochemical impedance spectroscopy (EIS), direct current (DC) polarization, and atomic absorption (AA) experiments were conducted at different time periods up to 150 days. EIS, DC, and AA results indicated that the passivation treatment with the lowest chromium content (Type 1) showed slightly worse corrosion behavior, with substantial iron dissolution and sulfur staining of the tinplate, than passivation treatments Types 2 and 3, which behaved similarly to each other. A fully opened can was used as the working electrode and electrolytic cell in contact with canned cockles (a mollusc, Cardium edulis).