An investigation of inhibition effect of Herba hyperici and Folium juglandis on the corrosion of mild steel

In this study, the effects of Folium Juglandis and Herba Hyperıcı expected being good corrosion inhibitors due to the their molecular structure on corrosion of mild steel were investigated at different pHs and at different extract concentrations. To obtain the experimental data AC impedance, polarization resistance measurement and polarization curves measurement techniques were used. The percent inhibition efficiency (IE%) values were determined in the presence of Folium Juglandis and Herba Hyperıcı. The results showed that inhibition efficiency change with pH and extract concentration. Results revealed that the extract of Folium Juglandis was an effective inhibitor at all pHs studied and, ıts protection efficiency was high enough especially at 100 ml/L concentration in 0.5 M Na2SO4. It was observed that the extract of Herba Hyperıcı increased corrosion rate of mild steel at pH 4 while it is an effective inhibitor for corrosion of mild steel at pH 6. It was also found that inhibition efficiency of the extract was fairly good at pH 8. Key Words: Mild steel, Folium Juglandis, Herba Hyperıcı, EIS, Corrosion inhibitors.