Study of Some Azo Derivatives as Corrosion Inhibitors for Mild Steel in 1 M H2SO4

Abstract

Six new azo derivatives were successfully prepared and investigated as corrosion inhibitors for mild steel in 1 M H₂SO₄ solution by weight loss measurements for 24 h at 30°C. It was observed that at higher inhibitor concentrations, the rate of corrosion decreases while the inhibition efficiency and the surface coverage degree increase. The values of the standard free energy of adsorption showed that all prepared azo derivatives have physisorption effects. The correlation between experimental results and theoretical data was considered via semi-empirical molecular orbital calculations for the six studied inhibitors. Theoretical calculations were used to understand the interaction nature between the metal surface and the organic molecules of the studied corrosion inhibitors.