| Aluminum alloys with magnesium are broadly applied as structural materials for their high ductility and remarkable corrosion resistance. As the strongest alloys of this system have low stability specifications, the present research aims to investigate the probability of making strong of Al--Mg alloy by doping silicon, germanium and tin. This work presents an analysis of the influence of some organic heterocyclic inhibitors owing to Langmuir adsorption and DFT and TD-DFT method with different process parameters, on the corrosion resistance of aluminum alloy containing Al-X--Y (X = Mg, Y = Si, Ge, Sn). The ONIOM approach has been performed with a three-layered level of high by CAM-B3LYP theoretical function using 6--31 + G (2d,p) and LANL2DZ basis sets applying Gaussian 16 revision C.01; a medium semi-active part that consists of essential electronic contributions; and a low level part that has been handled using MM2 force field approaches. The physicochemical properties of inhibitor → metal alloy complexes are evaluated with the Langmuir adsorption through NMR, NBO, UV--VIS, HOMO/LUMO and DOS/PDOS graphs toward structural, electronic and thermodynamic properties and other quantum attributes. The fluctuation of occupancy of natural bond orbitals has been estimated for [pyridine,2-picoline,3-picoline,4-picoline, 2,4-lutidine → Al--Mg--(Si, Ge, Sn)] concerning the influence of nitrogen atom in the benzene ring of related heterocyclic compounds becoming close to the monolayer nanosurface of Al-X--Y (X = Mg, Y = Si, Ge, Sn) alloys. Furthermore, the results of partial electron density states (PDOS) have confirmed an obvious charge accumulation between the Al--Mg alloy and doped atoms of Si, Ge, and Sn through the recognition of the conduction band region. Based on the computed values of UV--VIS spectrums for pyridine, 2-picolone, 3-picoline, 4-picoline and 2,4-lutidine adsorbed on the Al--Mg-Y (Y = Si/Ge/Sn) alloys surface, there are maximum adsorption band wavelengths between 1000 nm and 4000 nm, respectively. In addition, it has been observed the sharpest peak in 2250 nm for all of these inhibitors adsorbed on the Al--Mg-Y (Y = Si/Ge/Sn) alloys surface. This study revealed that appropriate control of the coating process by Langmuir adsorption can illustrate inhibiting the aluminum alloys corrosion through an investigation of their structural, electronic and thermodynamic properties. |
Dr. Öğr. Üyesi Fatemeh MOLLAAMIN
Majid Monajjemi
