Corrosion behavior of carbon steel coated with magnesium electrodeposited from methyl magnesium chloride solution
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- Hassen, S.B., Bousselmi, L., Rezrazi, E.M. et al. J Coat Technol Res (2013) 10: 277. doi:10.1007/s11998-012-9436-4
Magnesium coating was electroplated on carbon steel to improve its corrosion protection. The analytical characterization of the magnesium coating was performed by scanning electron spectroscopy and energy dispersive X-ray spectroscopy. The electrochemical behavior of Mg-coated carbon steel was assessed by electrochemical impedance spectroscopy, open-circuit potential measurements and potentiodynamic polarization curves in 0.03% sodium chloride solution. The electrochemical results showed that the self-corrosion current density (icorr) of magnesium-coated steel was 0.32 mA cm−2 (about 1.8% of that of uncoated steel). Impedance results showed an increase of the total impedance when magnesium coating was applied on steel substrate. The corrosion protection was ensured by a two-step mechanism. The first step was cathodic polarization; the second step was the formation of a barrier due to magnesium oxides composed of MgO, Mg(OH2) and Mg(OH3)Cl.