Aluminum Corrosion Inhibition by 2,6-diaminopyridine in 3.5% NaCl: Tafel Polarization, Surface and Quantum Chemical Study

The inhibition property of 2,6-diaminopyridine for aluminum in 3.5% NaCl was carried out by using Tafel polarization, Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and quantum chemical methods. Tafel polarization study reveals that inhibitor is of mixed type but predominantly anodic. The maximum inhibition is 98.5% at 100 mg/L. Surface analysis (SEM and AFM) supports the formation of a protective inhibitor film on the aluminum surface. Quantum chemical calculation has performed for both neutral and protonated molecules in order to study the effect of molecular structure on inhibition efficiency.