Cysteine and cerium as green corrosion inhibitors for AA7049: Mixture vs. complexation

In this work new green corrosion inhibitors based on the synthesized cerium-cysteine complex on AA7049 aluminum alloy were analyzed and compared to the mixture of CeCl 3 and cysteine in 0.1 M NaCl. The complex structures were confirmed by FTIR, NMR and Elemental Analysis. It was shown that cerium was present in two oxidation states, Ce III and Ce IV , when the mixture was analyzed, while there was only a Ce IV oxidation state in the cerium-cysteine complex. The mechanisms of inhibitory action of the joint effect of CeCl 3 and cysteine vs. their complex were proposed and analyzed in more detail. • The inhibitory effects of CeCl 3 , cysteine, their mixture and complex were compared • Mixture showed high coverage of IMPs and the best inhibitory effect • Structure of Ce-Cys complex was confirmed by FTIR, NMR and elemental analysis • Both Ce III and Ce IV oxidation states are present in mixture and only Ce IV in complex