Silicon Content Affecting Corrosion Behavior of Al_p/Si_p Composites in a Biodiesel Blend

This study is focused on the evaluation of the electrochemical behavior of three distinct Al_p/Si_p composites (i.e., 2.5 wt%, 5.0 wt%, and 7.5 wt% Si). In contrast to the stirring casting process, the composites are produced using both Al and Si powders (i.e., mixing, compacting, and sintering). The samples are immersed in a stagnant and naturally aerated biodiesel + ethanol blend, using lithium perchlorate (LiClO₄) as a supporting electrolyte, at 25°C. Electrochemical impedance spectroscopy diagrams and equivalent circuits are analyzed and discussed. The densification levels and Si content affect the corrosion resistance responses. A “recovery” in the corrosion behavior in terms of impedance parameters of Al/7.5 Si composite is attained.