Performance and degradation analyses of traditional and ECCS canning tinplates in citric-citrate medium

In order to evaluate the degradation of aluminum- and gold-plated epoxyphenolic coatings found in traditional tinplates and electrolytic chrome-coated steel plates (ECCS) co-rolled with polyethylene teraphthalate (PET) used as canning materials in food products, an immersion procedure in a special device containing an citric-citrate medium was performed during a 12-month period. The influence of the porosity of polymer coatings on the physicochemical interactions at an interface level between the metal substrates and protection films of tinplates was analyzed by standardized tests. The damage morphology on both tinplates and the intensity of the attack in function of the ionic dissolutions in the solution were characterized.