Magnesium alloys are the worlds lightest structural metals, with an extraordinary growth potential inview of the accelerating demands for light-weighting materials in portable devices andtransportation (aerospace, automotive). However, this material class has poor corrosion resistanceproperties and, therefore, requires an efficient protective system. Furthermore, due to health issuesconcerning Cr VI - based anti-corrosion compounds, the mentioned sectors urge for thedevelopment of new environmentally friendly corrosion inhibitors. Fast, effective and irreversiblepassivation is an essential protection of magnesium alloys. Since a few years, lithium-salts gainedincreasing interest as a potential alternative for chromates for corrosion protection of aluminumalloys.In this paper, the authors present a comparative study of the active protective properties ofcerium, lanthanum and lithium salts on AZ31 magnesium alloy, aiming at improving theunderstanding of the inhibition behavior for long immersion periods in an aqueous electrolyte. Theinfluence of counter ions of the salt inhibitor has also been investigated. The morphology of thesurface was studied using Scanning Electron Microscopy (SEM). The electrochemical activity ofthe inhibitors in sodium chloride solution was studied versus immersion time using ElectrochemicalImpedance Spectroscopy (EIS) and anodic and cathodic polarization curves. The composition ofthe film formed in the surface were analyzed using X-ray Photoelectron Spectroscopy (XPS). Aprotection mechanism is proposed.
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