The corrosion inhibition of aluminum alloy surface (6063AA) by Sildenafil (SIL) in 1 M for both HCl and
NaOH solutions was investigated using weight loss, electrochemical techniques and quantum calculations.
The inhibitory effect of SIL was explained by the formation of the complex adsorbed on the
6063AA surface. The adsorption obeyed Langmuir isotherm. The adsorption of the SIL is a mix of physical
and chemical adsorption, where the free energy of adsorption was found to equal 39.12 and
34.6 KJ/mol, in HCl and NaOH, respectively. Experimental outcomes showed that SIL significantly inhibits
the dissolution of 6063Al in both acidic and alkaline media. SIL drug acts as a mixed inhibitor in both
two aggressive solutions. The correlation of the inhibition performance of SIL on 6063Al with the molecular
structure was adopted using Dmol3 (Materials Studio v7. 0) based on some descriptors as EHOMO and
ELUMO. Fukui indices were computed to determine the active sites of the inhibitor molecules. The equilibrium
adsorption behavior of SIL on Al (111) surface was examined using molecular dynamics simulation.
The quantum chemical descriptors were found suitable in explaining the inhibitive action of SIL. |
