THE INHIBITORY EFFECT OF SOME BIPYRIDINE DERIVATIVES ON THE CORROSION BEHAVIOR OF<font>N</font>80 CARBON STEEL IN SULPHURIC ACID SOLUTIONS

Abstract

The corrosion inhibition characteristics of 2,2′-bipyridine (BIPY) and 2,2′-bipyridine-3,3′-dicarboxylic acid (BIDA), on carbon steel in sulphuric acid solutions was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques at 20°C, 30°C and 40°C. The results indicate that the organic compounds inhibit the corrosion of mild steel in H 2 SO 4 solutions and the extent of inhibition increases with inhibitor concentration and decreases with temperature. A mixed-inhibition mechanism is proposed for the inhibitive effects of the compounds. The order of inhibition efficiency obtained was BIDA&gt;BIPY. There is a good correlation between the quantum chemical parameters and experimentally determined inhibition efficiency of the inhibitors. The adsorption characteristics of the inhibitor were approximated by Temkin isotherm. Morphological study of the carbon steel electrode surface was undertaken by scanning electron microscope (SEM) and the interfacial species formed on the surface in the presence of inhibitors analyzed by Infrared spectroscopy.