Quantum chemical studies on inhibition effect of amino acids and hydroxy carboxylic acids on pitting corrosion of aluminium alloy 7075 in NaCl solution

Quantum chemical calculations were performed on six amino acids and six hydroxy carboxylic acids. Possible correlations between experimentally obtained inhibition efficiencies (ΔE) for pitting corrosion of Al 7075 alloy in NaCl solution and parameters such as electronic charges on active centres (qO, qN), dipole moment (μ), highest occupied (EH) and lowest unoccupied (EL) molecular orbital energies and the differences between them (EL−EH), HOMO-LUMO gap were investigated. Possible inhibition mechanism for pitting corrosion of Al 7075 in NaCl solution was proposed from the obtained relations between quantum chemical parameters computed using AM1 and PM3 methods and experimentally obtained inhibition efficiencies.