Corrosion inhibition mechanism of 2,6-pyridinedicarboxylate depending on magnesium surface treatment
Ci Song, Cheng Wang, Dimitri Mercier, Bahram Vaghefinazari, Antoine Seyeux, Darya Snihirova, D. C. Florian Wieland, Philippe Marcus, Mikhail L. Zheludkevich, Sviatlana V. Lamaka
Abstract
2,6-pyridinedicarboxylate (2,6-PDC) was studied as corrosion inhibitor for pure magnesium. The surface was prepared either by polishing or polishing followed by treatment with 1 M NaOH solution. The results show that 2,6-PDC promotes the formation of a denser protective oxide/hydroxide layer poor in PDC. The mechanism proposed includes forming weak PDC-Mg complexes that lower the free Mg2+ concentration available for the formation of Mg(OH)2. This leads to growth of smaller Mg(OH)2 platelets that are more densely packed and hence form a more protective layer. The highest inhibition efficiency of 2,6-PDC was achieved for samples with surface hydroxylated by NaOH treatment.