Effect of Vanadium Pentoxide (V2O5) on the Corrosion Protection Performance of Zn-Mn-V2O5 Composite Coating on Mild Steel

The electrodeposit of Zn-Mn-V2O5 alloy composite coating has been obtained on the surface of steel using acid sulphate bath. The bath composition and operating variables such as pH, current density and temperature were optimized through Hull-cell experiments. The corrosion properties of Zn, Zn-Mn and Zn-Mn-V2O5 have been studied in 3.5% wt. NaCl using potentiodyanamic polarization measurements like Tafel extrapolation and which showed the corrosion rates (CR) of 7.234×10-5 g h-1, 5.392×10-5 g h-1, and 2.909×10-6 g h-1, respectively. The polarization resistance (RP) values of 938.9 Ω cm2, 3403.8 Ω cm2 and 4287.5 Ω cm2 by electrochemical impedance spectroscopy (EIS) also confirm the better corrosion resistance of Zn-Mn-V2O5 compare to Zn, Zn-Mn alloy coatings. The current efficiency and throwing power of the optimized bath solution were measured. The surface morphology of Zn-Mn-V2O5 composite coating has been analyzed by SEM. The X-ray diffraction analysis (XRD) was employed to study the average crystallite size of the composite coatings.