CORROSION INHIBITION AND ADSORPTION BEHAVIOR OF SOME AZO DYE DERIVATIVES ON CARBON STEEL IN ACIDIC MEDIUM: SYNERGISTIC EFFECT OF HALIDE IONS

Abstract

Corrosion inhibition of carbon steel in HCl by azo dye derivatives (ADD) was investigated using chemical and electrochemical techniques. Results obtained indicate that ADD inhibited the corrosion of carbon steel in the acid medium. Inhibition efficiency increases with increase in ADD concentration and is synergistically enhanced on addition of iodide and bromide ions. By fitting the obtained experimental data with the Langmuir adsorption model and the Arrhenius equation, some thermodynamic and kinetic parameters for the corrosion process were estimated, and the values support the results obtained. Some quantum chemical parameters and the Mulliken charge densities for ADD were calculated by the MNDO semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process.