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The inhibition effect of a Schiff base with several functional groups on the corrosion of aluminum in alkaline solution is studied by experimental techniques and density function theory (DFT) calculations. The Schiff base are characterized by 1 HNMR, 13 CNMR, FT-IR, and CHN elemental analysis. In addition, different electrochemical and corrosion techniques such as weight loss, tafel polarization, electrochemical impedance spectroscopy (EIS) and optical microscopy images are performed to analyze the inhibiting performances. In the Tafel measurements the cathodic Tafel slopes values incurred small changes with increasing the inhibitor concentration, which revealed that the inhibitor was adsorbed on the aluminum surface. The inhibition efficiencies are calculated from weight loss measurement and electrochemical tests. The adsorption of the inhibitor onto the aluminum surface follows the Langmuir adsorption isotherm with the free adsorption energy of −8.66 kJ mol −1 . The calculated adsorption energies and the amount of charge transfer obtained by DFT calculation revealed that corrosion inhibition effectively occurs with chemisorption, where new N Al bonds are formed between of N atoms in azo (–N N–) group and Al surface atoms, which is confirmed from ab initio molecular dynamics (AIMD) simulation. [ABSTRACT FROM AUTHOR]

The electrochemical performance of Al, Al–0.5 Mg–0.1 Sn–0.03 Ga–0.007 Pb (Alloy 1) and Al–0.5 Mg–0.1 Sn–0.05 Ga–0.07 Pb (Alloy 2) (wt.%) in 2 M NaCl solution has been investigated by using open circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy and galvanostatic discharge. The results suggest that the protective oxide layer on the Alloy 2 is unstable and pitting corrosion in weak points is evident while the Al surface is covered with passive layer. The addition of lead and gallium alloying elements to aluminum causes significant activation of aluminum. Gallium and tin as alloying additives in alloy composition can result in the adsorption of Cl − ions in the active sites at more electronegative potentials and therefore activate the alloy. The activation is revealed by shifting the open circuit potential in the negative direction, considerable increasing of corrosion current density and removal of the passive potential region. The extent of activation depends on the amount of the alloying elements and there is an increase in the following order: Al < Alloy 1 < Alloy 2. The galvanostatic discharge tests, combined with the results of impedance and potentiodynamic polarization confirmed the great activity of Alloy 2 compared to Alloy 1 and Al. [ABSTRACT FROM AUTHOR]