The acid corrosion inhibition process of copper in 2 M H3PO4, containing 0.3 M of
NaCl by an eco-friendly ionic liquid, 1-pentyl pyridazinium bromide (PPB), has been
investigated using weight loss measurements, potentiodynamic polarization and
electrochemical impedance spectroscopy (EIS).The effect of temperature on the
corrosion behavior with the addition of PPB was studied in the temperature range 298–
328 K. The value of inhibition efficiency decreases slightly with the increase in
temperature. Results show that PPB is a good inhibitor and inhibition efficiency reaches
91 % at 10-3 M. Gravimetric essays indicate that PPB inhibits the corrosion of copper
and the value of inhibition efficiency reaches 90 % at 10-3 M of the inhibitor.
Potentiodynamic polarization curves showed that the PPB affects both cathodic
and anodic current and may be classified as a mixed type inhibitor in (2 M H3PO4
+ 0.3 M NaCl). For the inhibitor, the inhibition efficiency increased with an increase in
the concentration. The adsorption of this compound on copper surface obeys
Langmuir’s adsorption isotherm. To elaborate the mechanism of corrosion inhibition,
the kinetic and thermodynamic parameters for copper corrosion and inhibitor
adsorption, respectively, were determined and discussed. Inhibition efficiency values obtained from weight loss, polarization curves and EIS are reasonably in good agreement. Theoretical calculations provide good support to experimental results.