EVALUACIÓN DE LA INHIBICIÓN DE CORROSIÓN EN ACEROS INDUSTRIALES CON MOLÉCULAS ORGÁNICAS DE NOPAL

Abstract

This research-dissertation sustains an electrochemical study of corrosion green inhibitor as ecological effects to the industry´s environment. A natural liquid extract obtained from Nopal plant, EN (scientific name: Opuntia Ficus Indica), has been studied as possible corrosion inhibitor of carbon steels during acid exposure, by applying electrochemical techniques, such as Linear Polarization Resistance-RP and Electrochemical Impedance Spectroscopy-EIS. Industrial carbon-steel were used as working samples in this research, AISI-1018 (structural & machinery application), AISI-1045 (structural steel grade) and the steel type AISI 4140 (machinery uses). These metals-samples were exposed to an aggressive aqueous solution of H2SO4 0.6M or a mixture of inhibitor/acid solution. On the other hand, studies of weight loss or weight gain were also carried out on standard coupons of carbon steel after exposure to evaluate the corrosion rate in the presence or absence of natural inhibitor (Nopal liquid-extract) during a pre-determined time, this study is confirmed by photographs that were taken day by day during the corrosion exposure. Through the analysis of EIS data it was demonstrated that some additions of the Nopal extract (EN) decreases significantly the corrosion rate (Vcorr) in 0.6M H2SO4 for the different studied steels, also the corrosion current (icorr) resulted lower. Therefore, an acceptable results of the corrosion inhibition efficiency (%IE) were obtained, reaching values of about 98%. Then, this research-dissertation indicates that under the experimental conditions of the corrosion test it can be considered the nopal plant as an alternative of corrosion inhibitor for steel in acid exposure. Finally, this research suggests that EN-inhibitor must be applied in the industry of materials manufacturing as many uses for the prevention and control of corrosion damage.