Corrosion Behavior of AlMgSi Alloy in Aqueous Saline Solution

摘要

The corrosion behavior of AlMgSi alloy in a solution of 3.5 % NaCl in H2O as a function of time ofimmersion has been studied and assessed by means of electrochemical techniques. These includedpotentiodynamic polarization curves, linear polarization resistance (LPR), electrochemical impedancespectroscopy (EIS) measurements and electrochemical noise measurements (EN). The corrosion rateexpressed in terms of corrosion current density of AlMgSi alloy resulted higher than that of pureAluminum. The precipitation of Mg2Si phase and the formation of the galvanic couple Al-Mg induceda shift of the current density towards higher values. According to electrochemical noise measurements,the Al-based alloy experienced a localized type of corrosion at virtually all the time of exposure. Thehydroxide or oxide films formed over the surface of AlMgSi alloy were not totally protective. Theelectrochemical behavior of corrosion has been explained in terms of the stability of the corrosionproducts formed film.