Titanium-Passivated Tinplate for Canning Foods

Chromium-based treatments are currently used for the passivation of tinplate, which produces a protective surface layer consisting of a mixture of metal chromium and chromium oxide. This passivation film is effective against the formation of tin oxides and corrosion by food media, and offers a good substrate for the adhesion of protective organic coatings. However, there is an increasing concern about environmental and health risks with this passivation treatment. The aim of this paper was to study a new environmental friendly passivation treatment based on a titanium compound, applied on tinplate and afterwards lacquered with a conventional epoxyphenolic lacquer used for food can applications. The mechanical and electrochemical characteristics of the lacquered material and the metallic dissolution in canned sardines in tomato juice and peeled tomato were similar to those obtained with conventional Cr-passivated tinplate. According to these results titanium treatment could be considered an alternative to chromium for practical applications.