Azodyes as corrosion inhibitors for dissolution of Csteel in hydrochloric acid solution

Abstract

The effect of some mono azo dye compounds on the dissolution of carbon steel (type L-52) in 2 M hydrochloric
acid solution was studied using weight loss and galvanostatic polarization techniques. The inhibition efficiency
was found to increase with increasing inhibitor concentration and decreasing temperatures. Inhibition was
explained by formation of insoluble complex adsorbed on the metal surface. The adsorption follows Langmuir
adsorption isotherm. The formation of stable complex was studied by conductometric titration. The
stiochiometric ratio was found to be 1:1; 1:2 for Fe
2+
/ dye compounds and the mechanism of inhibition was
explained in terms of these values. The thermodynamic functions of adsorption process was calculated and
discussed.