New synthesised pyridazine derivatives as effective inhibitors for the corrosion of pure iron in HC1 medium

The inhibition of pure iron in 1 M HCl by new synthesised pyridazine compounds has been studied by weight loss, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) measurements. The results obtained reveal that these compounds are efficient inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration and reached 98% at 10(-4) M for 5-benzyl-6-methyl pyridazine-3-thione. Potentiodynamic polarisation studies clearly reveal that the presence of pyridazines does not change the mechanism of hydrogen evolution and that they act essentially as cathodic inhibitors. The temperature effect on the corrosion behaviour of pure iron in 1 M HCl without and with the pyridazines at 10(-4) M was studied in the temperature range from 298 to 353 K. EIS measurements show that the increase of the transfer resistance with the inhibitor concentration. (C) 2002 Elsevier Science B.V. All rights reserved.