Electrochemical and Gravimetric Evaluation of 7-methyl-2-phenylimidazo[1,2-á]pyridine of Carbon Steel Corrosion in Phosphoric Acid Solution

摘要

The inhibition effect of 7-methyl-2-phenylimidazo[1,2-]pyridine (PIP) on the corrosion of carbon steelin phosphoric acid solution was investigated for the first time by weight loss, potentiodynamicpolarization, electrochemical impedance spectroscopy (EIS) and quantum chemicals calculations. Itwas observed that inhibition efficiency increased with increasing inhibitor concentration.Potentiodynamic polarization studies show that PIP acts as a mixed type inhibitor. AC impedanceresults were interpreted using an equivalent circuit in which a constant phase element (CPE) was usedin place of a double layer capacitance (Cdl) in order to give more accurate fit to the experimentalresults. The kinetic data such as apparent activation energies and pre-exponential factors at optimumconcentration of the inhibitor were calculated and discussed. Adsorption of PIP molecules on carbonsteel surface was found to obey the Langmuir adsorption isotherm. The relations between quantumchemical parameters and corrosion inhibition efficiency have been discussed to see if there is anycorrelation between the two of them.