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

Abstract

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 CeCl3 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, CeIII and CeIV, when the mixture was analyzed, while there was only a CeIV oxidation state in the cerium-cysteine complex. The mechanisms of inhibitory action of the joint effect of CeCl3 and cysteine vs. their complex were proposed and analyzed in more detail.