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This study is focused on the evaluation of the electrochemical behavior of three distinct Alp/Sip composites (i.e. 2.5, 5.0 and 7.5 wt.% Si). Differently from the stirring casting, 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 LiClO4) at 25oC. Electrochemical impedance spectroscopy (EIS) diagrams and equivalent circuit are analyzed and discussed. The densification levels and Si content affect the corrosion resistance responses. A “recovering” in the corrosion behavior in terms of impedance parameters of Al/7.5Si composite is attained.

Al and its alloys constitute one of the most versatile, economical, and attractive materials for a wide range of applications. The 7xxx and 2xxx series alloys achieve the highest mechanical strength among the aluminum alloys. In this investigation, powder metallurgy is used to characterize the microstructural and mechanical properties of a noncommercial Al6Cu5Zn alloy. Initial powder sizes are determined, and the best conditions are obtained for distribution between 75 and 106 μm. The samples are sintered at 585 °C, 600 °C and 615 °C for 0.5, 1.5 h and 3 h. Similar mechanical behavior to that of the as-cast Al-Cu-based alloys is attained (~125 MPa) for the samples sintered at 615 °C for 3 h. In terms of a reduction in energy consumption and in the metal fumes commonly evidenced by foundry applications, Al-Zn powders have the potential to be associated with Al and Cu powders in an Al6Cu5Zn composite constitution.

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