Characterization of passivated tinplate for food can applications

Abstract

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.