Our results demonstrated that the introduction of molybdate ions into 0.05 M NaCl solution dramatically changes the corrosion behavior of all examined AZ31-xLi alloys. Dissolved molybdates retard corrosion attack by forming a protective insoluble film over the active surface areas of all alloys. Nevertheless, as for other Mg alloys , it is essential to achieve a "critical" concentration of molybdate inhibitor in the electrolyte to provide high inhibition effectiveness (Figs. ). Interestingly, the results of instant g-DEIS measurements report inhibition effectiveness even for small portions of the inhibition (Fig. ). However, utilization of low concentrations of molybdates seems to be inefficient at long exposure times. Therefore, in the mechanism below we assume relatively high concentrations of the inhibitor in the solution (above 100 mM) to provide reliable inhibition.