N-benzyl-N,N-bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]amine as corrosion inhibitor of steel in 1 M HCl

The inhibition effect of a new bipyrazole derivative namely N-benzyl-N,N-bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]amine (BBPA) on the corrosion of steel in 1 M HCl is studied at 308 K. Weight-loss measurements, potentiodynamic polarisation, linear polarisation and impedance spectroscopy (EIS) methods were used. Results show that BBPA is a good inhibitor and inhibition efficiency reaches 87% at 5 · 10− 4 M. The values of the inhibition efficiency calculated from these techniques are reasonably in good agreement. Polarisation curves revealed that this organic compound acts as a mixed-type inhibitor. The temperature effect on the corrosion behaviour of steel in 1 M HCl with and without BBPA at 5 · 10− 4 M is studied in the temperature range 308–353 K. The associated activation energy is determined. The adsorption of BBPA on the steel surface obeys to the Langmuir's adsorption isotherm. EIS measurements show that the transfer resistance increases with the inhibitor concentration. Efficiency is explained by the theoretical studies.