Electrochemical studies of phenyl sulphonyl ethanone derivatives compounds on corrosion of aluminum in 0.5 M H2SO4 solutions

Abstract

Inhibition influence of phenyl sulphonyl ethanone derivatives (PSED) on corrosion of aluminum in 0.5M H2SO4 solutions were investigated by many techniques namely potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) supplemented by studying the surface morphology using scanning electron microscope (SEM). Potentiodynamic polarization measurements showed that the investigated compounds act as mixed type inhibitors. The inhibition efficiency increases by increasing compounds concentration, but decreases by raising temperature. Electrochemical impedance spectroscopy was used to investigate the mechanism of corrosion inhibition. Electrochemical frequency modulation results indicates that each spectrum is a current response as a function of frequency. A kinetic model and the Langmuir adsorption isotherm well fit the experimental data. The scanning electron microscope results showed the formation of a protective film on the metal surface in the presence of investigated compounds. According to molecular dynamics simulations the investigated compounds have been simulated as adsorbate on Al (1 1 1) substrate and the adsorption energy have been identified o aluminum surface. Some quantum chemical parameters were calculated to improve further insight into the mechanism of inhibition of the corrosion process.