Inhibition Efficiency of Silver-Gold Alloy Nanoparticles on Corrosion of Mild Steel, Stainless Steel and Aluminium in 3.5 M NaCl Medium

J.K. Odusote, T.B. Asafa, E.O. Shonubi
University of Ilorin,
Nigeria

Keywords: silver-gold alloy nanoparticle, gravimetric, gasometric, potentiodynamic polarization

Summary:

Several failures of equipment and structures in chemical industries have been attributed to corrosion. Most developed nations spend about 4% of their national GDP to prevent corrosion or repair failed structures emanated therefrom. Although a large number of corrosion inhibitors have been developed over the years, modification of inhibition mechanism by adding nanoparticles have been reported to improve efficiency of most inhibitors. In this paper, we reported the influence of silver-gold alloy nanoparticles (Ag-AuNPs) on the corrosion behavior of mild steel, aluminum and stainless steel in 3.5M NaCl using gravimetric, gasometric and potentiodynamic polarization techniques. Ag-AuNPs were synthesized via green chemistry and were characterized using FTIR, UV-Vis and TEM. Five concentrations of Ag-AuNPs (0 µg/ml, 5µg/ml, 10µg/ml, 15µg/ml, 20µg/ml) were added to 3.5M NaCl. After 2000 hours of exposure, gravimetric study showed that weight loss was reduced by ~85% translating to ~92% reduction in corrosion rate for the solution containing 20µg/ml of Ag-AuNPs. The equivalent inhibition efficiency was 89%, 94% and 96% for aluminum, mild steel and stainless steel, respectively. Gasometric study revealed that no oxygen gas evolved during the experiment. Furthermore, potentiodynamic polarization results showed that the presence of Ag-AuNPs modified the mechanism of anodic dissolution by the formation of adsorption layer on the surface of the metal samples. These results indicated that Ag-AuNPs can be incorporated into existing inhibitors for minimizing the corrosion rate.