Investigation of Imidazole-Based corrosion inhibitor (PL-464) and corrosion behavior of X65 steel in Hydrochloric Acid

Hydrochloric acid is used in many industries. One of its applications is for boilers’ acid cleaning and well acidizing in the oil and gas industry. For the reduction of HCl corrosion on metal parts and installations, corrosion inhibitors are used. In this research, the effect of Imidazole-Based corrosion inhibitor PL-464 and the corrosion behavior of X65 steel in Hydrochloric Acid (HCl) is considered. Polarization and Electrochemical Impedance Spectroscopy (EIS) experiments without and with 50, 100, and 150 ppm of PL-464 corrosion inhibitor at 25, 40, and 60ºc in hydrochloric acid solution are done. The result of these experiments showed that PL-464 inhibits corrosion by surface adsorption mechanisms. As temperature increases, corrosion potential moves toward positive amounts, and inhibition efficiency decreases. Also, corrosion decreases as inhibitor concentration is increased. Weight loss experiment at 25, 60ºc without and with 50, 150 ppm inhibitor is done, which corrosion weight loss percent is decreased as inhibitor concentration is increased. SEM and EDAX analysis showed that the steel surface in solution without inhibitor is damaged and Fe picks are shorter with respect to steel in solution with inhibitor. The results are attributed to the adsorption of inhibitors onto the steel surfaces which protects the steel surface from dissolving in acid solution.