Corrosion behavior of an Al-Si casting and a sintered Al/Si composite immersed into biodiesel and blends

This investigation is focused on the corrosion evaluation of an as-cast Al-7.5 wt% Si alloy and an Al/7.5 wt% Si composite immersed into distinctive biofuels. Immersions up to ~6000 h into three distinctive fuels are evaluated. A biodiesel B100, a mixture 1:1 between biodiesel and commercial diesel (B50); and mixture among biodiesel, diesel and commercial bioethanol (BDE blend) are considered. A novelty concerns to the adopted manufacturing route for the composite sample preparation is proposed. Commercial pure Al powders and pure Si particles are used. This provides different resulting microstructural arrays and consequently the distinct cathode-to-anode area ratios are also provided. It is found that into all biofuels examined, the Al/Si composite has lower corrosion susceptibility than the as-cast sample. Also, it is also found that the composite sample has a decreased corrosion behavior with increasing the water content. On the other hand, the as-cast sample shows a higher corrosion rate than the as-cast sample.