Structural characterization and properties of the TiO2 film on tinplate

A TiO2 film as chromate replacement was prepared on tinplate using sol–gel method, and appears golden. Sulfide-stain resistance of the TiO2-treated, chromate-treated and untreated tinplates was evaluated using a cysteine tarnish test. Corrosion behavior of these tinplates in contact with 3.5% NaCl solution and 0.1 M citric–citrate buffer solution was investigated using electrochemical impedance spectroscopy (EIS) measurement. The results show that the TiO2 film is more effective in improving sulfide-stain resistance and corrosion protection property of tinplate compared with the chromate-passivation film. Moreover, the cross hatch test reveals that the TiO2-treated tinplate provides excellent adhesion to the epoxyphenolic lacquer. The morphology, composition and thickness of the TiO2 film on tinplate were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence spectrometry (XRF), respectively. According to the results, the TiO2 film is homogeneous and crack-free. The film mainly consists of TiO2, and the total titanium amount of the film is 0.0996 g/m2.