Electrochemical corrosion behaviour of aluminium 6063 alloy in neutral polluted medium

The corrosion behaviour of an aluminium 6063 alloy has been studied in a synthetic water similar to natural one, The techniques used consisted of an electrochemical measurement and surface examination by SEM coupled with EDAX analysis. Results obtained show that Al 6063 alloy presents a good corrosion resistance in unpolluted synthetic water by forming a protective oxide passive film in the surface. In polluted medium by cupric ions even at low concentration, the rupture of passivity and accelerated attack of Al 6063 alloy takes place. Addition of chromate ions in polluted synthetic water leads to the repassivation phenomenon and explains the good performance of Al 6063 alloy in such mediums.