Abstract

Alcoholic extracts of Spinach (SP) leaves was studied as corrosion inhibitor for mild steel in 0.5 M HCl using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The results of the study revealed that SP extracts inhibit mild steel corrosion through adsorption process following Langmuir adsorption isotherm. The protection efficiency increased with increase in inhibitor concentration and decreased with temperature. Polarization measurements indicated that the SP behaves as mixed type of inhibitor. EIS measurements showed that the charge transfer resistance increases with increase in the concentration of SP extracts. Various thermodynamic parameters such as activation energy, activation enthalpy and activation entropy were evaluated. Adsorption thermodynamic parameters were also computed and SEM was used to analyze the surface adsorbed film.

Keywords

Mild steel, Spinach leaves extracts, Corrosion, Polarization, Impedance