Corrosion behavior of tinplate in NaCl solution
(1. School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China;
2. School of Electronic Information Engineering, Tianjin University, Tianjin 300072, China)
2. School of Electronic Information Engineering, Tianjin University, Tianjin 300072, China)
Abstract: The corrosion process of tinplate in 0.5 mol/L NaCl solution was investigated using the electrochemical impedance spectroscopy (EIS), and the morphology and structure of the corrosion products were characterized by scanning electron microscope (SEM), scanning probe microscopy (SPM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that the resistance of tin coating, Rc, was essentially constant but the charge transfer resistance, Rct, decreased by 2 orders of magnitude, which indicated that the tin coating was not seriously corroded while the carbon steel substrate was corroded continuously. The corrosion of tinplate in 0.5 mol/L NaCl solution was mainly the dissolution of carbon steel substrate because of the defects in the tin layer and the corrosion product was mainly γ-FeOOH.
Key words: tinplate; corrosion behavior; electrochemical impedance spectroscopy; NaCl solution