Corrosion Behavior of Brass in Methanol-Gasoline Fuel Blends

Alcohols have become attractive alternate to fossil fuels in the present oil crisis scenario because they can be obtained from varieties of natural and man-made sources and can reduce greenhouse gases from automobile emissions. Methanol production from biomass is one of the ways to convert waste into energy resources. Also methanol can be used directly in engines without changing the structure of the engines. Hence, methanol is the most attractive alcohol to be blended with fossil fuels. But methanol is hygroscopic in nature, and water content is always present in methanol-gasoline mixture because of strong affinity between the two substances which is a key factor for corrosion. Materials which are in contact with fuel in automobile applications can be grouped in three major categories: ferrous alloys, non-ferrous alloys, and elastomers. Metallic materials can undergo corrosion and wear when in contact with fuels. Corrosion occurred on metal surfaces in alcohol fuel blends are mainly due to alcoholate corrosion. Materials such as copper and its alloys (bronze and brass) can be oxidized on contact with automotive fuels and form sediments. Copper and its alloys present in some parts of engine fuel system such as fuel pump, bearing, and injectors are the mostly affected. Hence, the corrosion behavior of brass in methanol-gasoline blends was studied by mass loss method and potentiodynamic polarization method at room temperature and 40 °C with different time periods. Oxides and hydroxides of copper and zinc formed on the brass surface and corrosion products have been confirmed by X-ray diffraction (XRD).