Effects of the use of support electrolytes in electrochemical tests of Al-4wt.% Mg alloy exposed to bioethanol fuel

ABSTRACT The growth of world energy demand directly affects the consumption of petroleum-based fuels, increasing the negative impact of the use of these fuels and the decrease of crude oil reserves. This creates an opportunity for the use of fuels that are more efficient, of low environmental impact and, above all, of a renewable nature. Bioethanol is a biofuel that complies with these characteristics, but it has some aggressiveness from the electrochemical plane over conventional metallic systems, requiring a good selection of materials for its use and handling. In the evaluation of the corrosion properties of metal materials exposed to bioethanol, the low conductivity of these organic compounds must be taken into account to avoid difficulties in the development of the tests and the misinterpretation of results. There are currently methods to compensate for the ohmic fall produced by the organic electrolytic medium, one of the most used being the addition of soluble salts in defined concentrations. This work evaluates the effects of the addition of different concentrations of CH3COOK and LiClO4 as support electrolyte to bioethanol, when electrochemical measurements of Potenciodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) are carried out by exposing an aluminum and magnesium alloy to said solution.