Abstract
Due to the increasing energy demand, the limited resources of fossil crude oil, and the need to reduce CO2-emissions, fuels from renewable energy sources are in the focus of consideration. In particular in the United States and the European countries, legal restrictions with regard to sustainable energy supply will accelerate this trend, for example, by establishing a requirement for a gradual increase of the ethanol content in gasoline fuels.
With respect to its corrosive impact, however, the use of ethanol blended gasoline fuels is not necessarily uncritical. Ethanol has hygroscopic properties and leads to an increased water solubility. As expected, with increasing content of ethanol, fuels tend to have a larger concentration of water. Along with the higher water content, there is also a risk to contaminate the fuel with corrosive ions such as chloride, for example by production or atmospheric exchange processes. The risk of corrosion damage depends on the solvation behavior of the corrosive components in the fuel and the adsorption reaction at the phase boundary layer between material and fuel.
In this study, the impact of corrosive components and their interactions in ethanol-containing gasoline fuels on the corrosion behavior of pure aluminum (UNS A91050) has been analyzed. Using the methods of statistical experimental design, the components water, chloride, and acetic acid were varied in different ethanol blended gasoline fuels. On the material side, corrosion features such as mass change, hole depth and corrosion morphology were investigated dependent on the fuel composition. The quantitative evaluation of the interactions was determined by means of the contrast method and the multi-dimensional linear regression mode. To transfer the results into industrial automotive application, the experiments have been carried out as immersion tests up to 60 0C in accordance to the established guideline of the German Association of the Automotive Industry VDA 230-207.