Effect of the anionic part of various Ce(III) salts on the corrosion inhibition efficiency of AA2024 aluminium alloy

Systematic investigations on the inhibitive efficiency of different Ce(III) salts against the corrosion of AA2024 in 0.01 M NaCl are performed. Various concentrations (from 10−5 to 10−2 M) for each Ce-salt are investigated after different exposure periods up to 600 h. Their inhibitive abilities were evaluated by: Linear Sweep Voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS) combined with SEM observation and EDX analysis. A strong influence of the Ce-salts anionic parts on the inhibitive efficiencies and the mechanism of the protective behaviour are found. The inhibitive efficiencies of the Ce(III) salts are ordered as: Ce(NO3)3 > (NH4)2Ce(NO3)5 > Ce2(SO4)3 > CeCl3.

► The inhibitive efficiencies of various Ce-salts against AA2024 corrosion.
► Various concentrations are investigated for different exposure periods.
► The anionic parts of the Ce-salts strongly affect on their inhibition ability.
► Two completely different kinds of pitting were found.
► The inhibition efficiencies order as: Ce(NO3)3 > (NH4)2Ce(NO3)5 > Ce2(SO4)3 > CeCl3.