Corrosion Inhibition of AZ31-xLi (x = 4, 8, 12) magnesium alloys in sodium chloride solutions by aqueous molybdate

Corrosion of lithium-containing AZ31 magnesium alloys AZ31- x Li ( x = 4, 8, and 12 wt%) has been examined in 0.05 M NaCl solution with and without 10–150 mM of Na 2 MoO 4 inhibitor. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and dynamic electrochemical impedance spectroscopy (DEIS) measurements were used to correlate the phase composition and microstructure of the alloys with their corrosion propensity and effectiveness of the molybdate inhibitor, giving high inhibition efficiency (>85%) at concentrations higher than ca. 35 mM. Post-corrosion microstructure, Raman, and X-ray photoelectron spectroscopy analyses allowed to provide the inhibition mechanism of AZ31- x Li alloys by molybdate ions. • Effectiveness of molybdate inhibitor towards AZ31- x Li ( x = 4, 8, and 12 wt%) Mg alloys has been examined. • Dynamic multisine impedance spectroscopy was utilized to examine corrosion and inhibition mechanisms. • Corrosion rate of AZ31- x Li alloys and the inhibition effect of molybdate strongly depend on the amount of Li in the alloys. • A mechanism of corrosion inhibition of AZ31- x Li ( x = 4, 8, and 12 wt%) Mg alloys by molybdate has been proposed.