The inhibitory effect of bis-2,6-(3,5-dimethylpyrazolyl)pyridine on the corrosion behaviour of mild steel in HCl solution

The inhibitory effect of bis-2,6-(3,5-dimethylpyrazolyl)pyridine (DPP) on the corrosion of steel in 2 M HCl solution has been studied using a chemical technique as weight loss and electrochemical techniques as potentiodynamic polarization, linear polarization and impedance spectroscopy. The inhibition efficiencies obtained from all the methods employed are in good agreement. Results obtained reveal this compound to be an efficient inhibitor. The inhibition efficiency increases with increasing concentration to reach 92% at 2.5 × 10−3 M. Studies clearly indicate this compound to act as a mixed inhibitor without affecting the cathodic reaction. Effect of temperature on the corrosion behaviour of iron in 2 M HCl with and without the inhibitor has been studied in the temperature range 298–328 K. The inhibitor is adsorbed on the surface according to the Langmuir adsorption isotherm. Some thermodynamic data have also been calculated.