Electrochemical Corrosion Behavior of Mild Steel in HCl and H₂SO₄ Solutions in Presence of Loquat Leaf Extract

摘要

The electrochemical corrosion behavior of mild steel in 0.5 M HCl and 0.5M H2SO4 solutions inpresence of loquat, Eriobotrya japonica [EB], leaf extract was studied using potentiodynamicpolarization, electrochemical impedance spectroscopy and Fourier infrared spectroscopy (FTIR)measurements. Tafel polarization studies revealed that EB acts as mixed type in hydrochloric andanodic type inhibitor in sulphuric acid solution. The impedance response consisted of characteristicdepressed semicircles clarifying that the corrosion process occurs under charge transfer control. Theinhibition efficiency of the leaf extract increased with increasing the concentration and decreased withtemperature. The results showed that EB is more efficient in 0.5 M HCl than in 0.5M H2SO4 solutions.Theoretical fitting of Temkin isotherm was tested to clarify the nature of adsorption on mild steelsurface. Thermodynamic parameters indicated that the inhibition of corrosion of mild steel by EB leafextract occurred by physical adsorption mechanism.