Inhibitive tendency of zinc gluconate for aluminium alloy in sulphuric acid solution

The corrosion inhibition of aluminium alloy in 0.5M H2SO4 solution in the presence of zinc gluconate at 301 K was investigated using weight loss and an electrochemical method. Surface analysis of the aluminium alloy sample was reviewed by a high resolution scanning electron microscope equipped with energy dispersive spectroscopy (HRSEM/ EDS). The readings were taken after 48 h for 28 days while the concentration of the inhibitor was varied from 0.5 to 2.0% g/v with an interval of 0.5. The result of the investigation shows that zinc gluconate has a good corrosion inhibition effect for aluminium alloy in 0.5 molar sulphuric acid solution and its efficiency attains more than 67% at 1.5% g/v concentration of zinc gluconate at 301 K. The potentiodynamic polarization data showed that zinc gluconate acts as a mixed type corrosion inhibitor. The adsorption of zinc gluconate on aluminium alloy has been found to obey Freundlich adsorption isotherm at all the concentration of zinc gluconate studied. The results obtained from different methods are in good agreement.