Corrosion Performance of the Zn Coatings on AISI 1212 Mild Steel in 0.5 M NaCl Medium: Influence of Thicknesses of Metallic Film

The study was carried out to evaluate the electrodeposited performance of electrolytic Zn coated between different thicknesses (Zn-10 μm and Zn-20 μm) and passivation process in protecting AISI 1212 mild steel (MS) from corrosion. Corrosion testing of both methods was performed in 0.5 M NaCl solution by ac impedance measurements (AIM) and Tafel polarization curves (TPC). The inhibition performance was studied by electrochemical and surface analysis techniques (FESEM-EDS, AFM, XRD), which revealed that high strength metallic film forms successfully after passivation applied on the surface in the chloride ions. The results showed that Zn-20 μm coating gave very low inhibition of MS corrosion in chloride solution (~45%), while MS coated with passivation process provided high-efficiency protection (~98%) to the surface. The film resistance (RLPR) obtained from the linear polarization method (LPM) was compatible with AIM method.