CORROSÃO E BIOCORROSÃO DO ALUMÍNIO AA 3003 EM MEIO DE BIODIESEL, DIESEL, ETANOL E GASOLINA

Abstract

Biofuels are derived from renewable sources and increasingly are inserted in the global energy matrix, so it is of utmost importance to know their properties. The contact of fuel with various metallic materials constituents of vehicles makes these materials susceptible to corrosion. Aluminium is a metal used in automotive components has interesting features of corrosion resistance, because reacts with atmospheric oxygen without degradation that occurs from its surface, instead, an oxide layer is formed which protects against corrosion. The ABNT standard establishes the method for determining corrosion in fuels, but it is exclusive to copper and fossil fuels, and corrosion is evaluated in a qualitative way. In this context, this study aimed to investigate the corrosion of aluminum alloy AA 3003 in the midst of biodiesel, diesel, ethanol and gasoline. The methodology used consisted of immersion of the metallic material in the fuels during a two months for later analysis by mass loss tests. Biocorrosion assays with a presence of Escherichia coli bacteria (E. coli) were also carried out. The samples were characterized by scanning electron microscopy, electrochemical impedance spectroscopy and anodic potentiodynamic polarization. There was no significant mass variation with the mass loss tests for all fuels, suggesting that aluminum, when immersed in fuel, does not suffer a severe corrosive process. The electrochemical results in general, the metal proved to be more protected against corrosion when immersed in fuels, particularly diesel, proved to be the most favorable, followed by biodiesel, ethanol and gasoline. Gasoline reduced the corrosion resistance, and this may be related to the presence of sulfur in its composition. The presence of E. coli only for gasoline was detrimental in its resistance to corrosion, for the other fuels the presence of the microorganisms inhibited the corrosive process. The results indicated that aluminum AA 3003 is metallic material suitable for use in the preparation of vehicle components that will be in contact with biodiesel, diesel, ethanol or gasoline, because in no case did a generalized corrosion process occur.