Development of Nonchromate-Treated Tinplate Having Excellent Resistance to Yellow Staining and Smudging

抄録

The resistance of nonchromate treated tinplate for powdered milk cans to yellow staining and smudging with the passage of time was studied. Anodic treatment in a sodium phosphate solution was found to be effective as a nonchromate treatment, and the resistance to smudging was found to be improved by adding catholic treatment as a pretreatment. The O/Sn ratio of the tinplate with anodic treatment determined by using AES was higher than that of tinplate with catholic treatment and the Fe/O ratio of the tinplate with anodic treatment scarcely increased with the passage of time. In addition, the refractive index and thickness of the tin oxide film with anodic treatment measured by ellipsometry scarcely changed after the passage of time, and the binding energy of Sn_3d XPS spectra of the tin oxide film with anodic treatment also hardly changed.