Corrosion inhibition of armco iron in 1 M HCl media by new bipyrazolic derivatives

New bipyrazolic compounds were synthesised and tested as a corrosion inhibitors of Armco Iron in 1 M HCl medium using weight loss, electrochemical polarisation and impedance measurements. Comparison of results showed that 1,3-bis(3,5-dimethylpyrazolyl) propane 3 (inh2) was the best inhibitor. The maximum inhibition efficiency was reached 93% at 10(-3) M. Inh2 adsorbs on the iron surface according to the Langmuir isotherm model. The inhibition efficiency of inh2 increases with the rise in temperature in the range 308-338 K. The apparent activation energy for iron corrosion has been determined. (C) 2000 Elsevier Science Ltd. All rights reserved.