Abstract
This study compares the electrochemical behaviour of three aluminium-silicon alloys in acidic and alkaline media by employing chemical, polarization and electrochemical impedance spectroscopy measurements in addition to scanning electron micrography. In general, aluminium-silicon alloys corrode at a rate higher than pure aluminium in these media. The corrosivity of the media was in the order of NaOH > H3PO4 > oxalic acid > H2SO4 > tartaric acid > succinic acid. The corrosion susceptibility of the alloys decreased in any of the study media as follows: Al - 11%, Si > Al - 7% Si > Al - 22% Si. The results were discussed taking into account the microstructural features of the alloys. While capacitive control was observed in H2SO4, resistive control was apparent in NaOH medium.