Corrosion Inhibition Propargyl Alcohol on Low Alloy Cr Steel in 0.5 M H_2SO-4 in the Absence and Presence of Potassium Iodide

The corrosion and inhibition behaviors of low alloy Cr steel in sulfuric acid in the presence of propargyl alcohol (PA) and potassium iodide (KI) have been studied using Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization method. It was found that the inhibition efficiency increased with PA concentration. The addition of potassium iodide to propargyl alcohol in solution increased the inhibition efficiency of propargyl alcohol. A synergistic effect was observed between KI and PA with optimum of concentration of 10 mMol propargyl alcohol + 0.01% potassium iodide. Adsorption of propargyl alcohol alone or in combination with potassium iodide on the metal surface obeyed the Langmuir adsorption isotherm and thermodynamic calculations revealed that that the adsorption of inhibitors were of physical nature. That suggest the presence of iodide ions in solution increases the surface coverage.