Electrochemical behavior of organic/inorganic films applied on tinplate in different aggressive media

• The tinplate behavior was investigated using two food-simulating solutions.
• The corrosion resistance is strongly dependent on the electrolyte.
• Better behavior is observed for samples in contact with chloride ions.
• Specimens immersed in the citric/citrate solution undergo severe attack.

The corrosion behavior of bare and coated tinplate samples was investigated using two different electrolytes: 0.1 M NaCl and 0.1 M citric acid/sodium citrate buffer solutions. A hybrid sol–gel film was synthesized to coat the tinplate samples. The study was performed by polarization and electrochemical impedance spectroscopy techniques. The morphology characterization was made by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction and mechanical profilometry techniques.The obtained results indicate that the corrosion resistance is strongly dependent on the electrolyte. Better behavior is observed for samples in contact with chloride ions, even though at the end of the experiment numerous pits are observed all over the surface. Samples immersed in the citric/citrate solution undergo severe attack, which can be associated with a faster tin dissolution in presence of citrate ions.