Aluminium Corrosion in Bioethanol/Gasoline Blends

In this work, the corrosion behavior of aluminum in different types of bioethanol/gasoline blends has been evaluated by using electrochemical techniques. Evaluated bioethanols included bioethanol from Apple, mango, orange and sugar cane in concentrations of 10 and 20%, whereas employed techniques included electrochemical impedance spectroscopy (EIS), electrochemical noise (EN) and linear polarization resistance (LPR) during 90 days. Corroded samples were analyzed in a scanning electronic microscope (SEM). Obtained results have shown that orange, apple and mango bioethanols/gasoline, in both concentrations, there is a decrease in the impedance value as compared to that for pure gasoline, with the highest corrosion rate exhibited by the sugar cane bioethanol. LPR results indicate that the mango bioethanol/gasolina blends exhibited similar corrosion rates to that exhibited by gasoline. On the other hand, EN measurements showed that in both pure gasoline and the 10% concentration noise reading showed indicating a high susceptibility towards localized type of corrosion, whereas those exhibited by th 20% concentration indicated a susceptibility towards uniform type of corrosion or passivation, which was corroborated by the SEM micrographs.