The analysis of the anodic Tafel slope, ba, showed a notable increase in the slope values in inhibited solutions for all studied alloys (Table ). The calculated values of icorr at low concentrations of the inhibitor (10 mM of Na2MoO4) increased for all examined alloys. This indicates that at low concentrations aqueous molybdate is not able to effectively passivate all active surface sites. This results in an increased current density over unprotected areas and, consequently, an increased corrosion rate. The same behavior was previously observed for the WE43 and AZ31 alloys in the case of the molybdate and permanganate inhibitors . At higher added concentrations, Na2MoO4 caused a pronounced decrease in icorr. The highest IE calculated by Eq. ( ) was 93-97% in solutions containing 150 mM of the inhibitor. However, the Tafel analysis of polarization curves in the case of the Mg alloys is not always straightforward. Therefore, to compare the effectiveness of the inhibition by molybdate, the values of the current densities iа and ic were extracted at selected potentials of -1.10 and -1.45 V, respectively, laying on anodic and cathodic branches of polarization curves. The anodic current densities decreased two orders of magnitude (150 mM of Na2MoO4), giving clear evidence of the corrosion inhibition due to the presence of the inhibitor.