Interfacial behavior of 4-(2-pyridylazo) resorcin between steel and hydrochloric acid

The interfacial behavior of 4-(2-pyridylazo) resorcin (PAR) between cold rolled steel and hydrochloric acid has been investigated by using weight loss and potentiodynamic polarization techniques. The adsorption of the inhibitor on the metal surface is found to accord with Langmuir adsorption isotherm. Some thermodynamic and dynamic parameters have been calculated and analyzed. Potentiodynamic polarization measurements clearly reveal that the investigated inhibitor is a cathodic inhibitor. The influence of temperature and acid concentration has also been studied in the presence of PAR in hydrochloric acid.