Corrosion Inhibitive Behaviour of the Natural Honey in Acidic Medium of A315 Mild and 304 Austenitic Stainless Steels

The corrosion inhibition performance of the natural honey in H2SO4 acidic medium containing mild steel and stainless steel, using weight loss and electrochemical techniques was investigated. The study involved the determination of the effects of the variation of the concentrations of natural honey inhibitor on the corrosion process. Potentiodynamic polarization for the electrochemical measurements was carried out by using Autolab PGSTAT 101 Metrohm potentiostat. Results obtained showed that increase in natural honey concentration (0–10 v/v%) retards the rate of metal dissolution and hence inhibits the corrosion of the metals. And the efficiency of the natural honey inhibitor increased with increased inhibitor concentration. The Tafel plots showed that the natural honey significantly decreased the corrosion potential (Ecorr) and current density (Jcorr); but increased the surface coverage (𝜃𝜃) and polarisation resistance. Adsorption and thermodynamics studies revealed that the Langmuir adsorption isotherm was obeyed and the large values of ∆𝐺𝐺𝑎𝑎𝑎𝑎𝑎𝑎obtained as well as its negative sign implied strong interaction and high efficiency of adsorption. SEM analysis of the metals (before and after corrosion) revealed significant reduction in corrosion rate as the concentrations of natural honey inhibitor increased