Characterization of Passivated Tinplate for Food Can Applications

By N. Mora, E. Cano , J.M. Bastidas, E. Almeida, J.M. Puente

Tinplate specimens for food can applications, passivated by cathodic treatment in a sodium dichromate solution, were studied. Three experi­mental methods: coulometric, spectrophotometric, and atomic absorption spectrophotometry (AAS), were used to quantify the chromium content in the passive coating as total chromium, metallic chro­mium, and chromium oxide.

Morphological and chemical analyses using scanning electron mi­croscopy (SEM) and energy dispersive X-ray (EDX) were performed. The study was completed by conducting X-ray photoelectron spectroscopy (XPS) experiments in order to elucidate the pas­sive layer chemical composition.