Corrosion inhibition of aluminum in 0.5 M HCl solutions containing phenyl sulfonylacetophenoneazo derivatives

The inhibition effect of some phenyl sulfonylacetophenoneazo derivatives (PSAAD) on the corrosion of Al in 0.5 M HCl solutions was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, and electrochemical frequency modulation. The results obtained showed that the addition of the PSAAD inhibits the hydrochloric acid corrosion of Al. Potentiodynamic polarization measurements showed that the PSAAD act as mixed type inhibitors but predominately act as cathodic inhibitors. The inhibition efficiency increases with increasing the PSAAD concentration, but decreases with increasing temperature. A kinetic model and the Langmuir adsorption isotherm fit the experimental data well. A good correlation was found between the theoretical data and the experimental results.