Aggressiveness of a 20% bioethanol–80% gasoline mixture on autoparts: I behavior of metallic materials and evaluation of their electrochemical properties

In this research, different metallic materials commonly used in the manufacture of autoparts were immersed in a 20% bioethanol–80% gasoline (E20) blends and their performance was evaluated. In order to determine the corrosive behavior and corrosion inhibition of these metals in the E20 blend, a continuous immersion test, a mass loss determination test, electrochemical impedance spectroscopy (EIS) and surface characterization were performed. EIS was carried out under both static and hydrodynamic conditions. Metallic materials evaluated were: aluminum–silicon alloy, chromium steel, carbon steel, stainless steel, aluminum, copper and tin. The immersion test indicated that carbon steel had the greatest susceptibility to corrosion in E20. According to the polarization resistance values (Rp) estimated by EIS, carbon steel and copper exposed to E20 exhibited a relatively high susceptibility to corrosion, while the other metals showed high Rp values indicating a low susceptibility to corrosion. The addition of 0.1 g l−1 of ethanolamine in the E20 mixture as a corrosion inhibitor for carbon steel was effective during the first 30 days of immersion.