期刊名称：Journal of Materials and Environmental Science
印刷版ISSN：2028-2508
出版年度：2015
卷号：6
期号：2
页码：425-444
出版社：University of Mohammed Premier Oujda
摘要：Corrosion inhibitio n of mild steel in 1 M H 2 SO 4 was investigated in the absence and presence of different concentrations of quinoxaline derivatives namely (3E)-3-(phenylimino)-3,4-dihydroquinoxalin -2(1H)-one (PDQO), (3E)-3-[(2-methylp henyl) imino]-3,4-dihydroquinoxalin-2(1H)-one (MPDQO) and (3 E)-3-[(2-methoxy-phenyl)imino]-3,4-dihydroquinoxalin-2(1H)- one (MOPDQO). Weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were emplo yed. Impedance measurements showed that the charge transfer resistance increased and double layer capacitance decreased with increase in the inhibitor concentration. Potentiodynamic polarization study showed that the inhibitors acted as mixed -type inhibitors. The adsorption of these co mpounds on the mild steel surface obeys a Langmuir adsorption isotherm. Results obtained reveal that compound MOPDQO is the best inhibitor and the inhibition efficiency follows the sequence: MOPDQO > MPDQO > PDQO. Electronic properties such as highest occupied molecular orbital (E HOMO ) and lowest unoccupied molecular orbital (E LUMO ), the energy difference (ΔE) between E HOMO and E LUMO , dipole moment (μ), electronegativity (χ), electron affinity (A), hardness (η), softness (σ), ionization poten tial (I), the fraction of electrons transferred (ΔN), total energy (TE) were calculated and discussed. The results sho wed that the corrosion inhibition efficiency increased with an increase in the E HOMO values but decrease in the E LUMO values. Mulliken ato mic charges, Fukui functions and softness indices were discussed in order to characterize the inhibition property of the inhibitors.
