Employing Cyclic Stress for Studying Corrosion and Corrosion Inhibition of C-Steel in Aqueous Solutions

The inhibitive effect of some organic derivatives on the corrosion of cyclic stressed C-steel specimens in 2 M HCl in the presence of organic derivatives with concentrations (1×10-6 M – 11×10-6 M) at 30 oC was studied using galvanostatic polarization, and weight loss techniques. The inhibiting effect was attributed to the adsorption of the additives on the C- steel surface. The data obtained fit well to Frumkin adsorption isotherm. The results of polarization studies indicate that the investigated organic derivatives are mixed type inhibitors. The presence of the inhibitors with the aggressive solution 2 M HCl improves of the relative reduction of fatigue life of the C-steel. The presence of the studied compounds solution inhibits both the hydrogen evolution and the anodic dissolution processes with overall shift of Ecorr to more negative values with respect to the OCP. The increase in the inhibition efficiency of investigated inhibitors with the addition of iodide ions indicates that iodide ions play important role in the adsorption process. The efficiencies obtained from the three different techniques were in good agreement which prove the validity of these tools in the measurements of the tested inhibitors.