SYNERGISTIC EFFECT OF IODIDE IONS ON THE CORROSION INHIBITION OF CARBON STEEL BY HEXAMETHYLENETETRAMINE IN THE WATER AND “CONDENSATE/WATER” EMULSIONS

Abstract

The synergistic action caused by iodide ions (I-) on the corrosion inhibition of carbon steel in the water and “condensate/water” emulsions in the presence of Hexamethylenetetramine  (C6H12N4) has been investigated using mass-loss measurements, potentiodynamic polarization, linear polarization and lectrochemical impedance techniques. Hexamethylenetetramine (Hexa)

inhibits the corrosion of carbon steel even at lower concentrations. The steel corrosion inhibition efficiency of Hexa is increased with increasing concentration of iodide ions and with decreased of water content in condensate/water” emulsions. The steel corrosion inhibition efficiency by “Hexa (2 g/l) + KI (0, 0.5, 1, 2 g/l)” mixture is increased significantly with dissolved oxygen exclusion from water. The highest steel corrosion inhibition efficiency by “Hexa (2 g/l) + KI (0,0.5, 1, 2 g/l)” mixture in the water is observed at 100 0C in the temperature range from 30 oC to

140 oC. The mechanism of corrosion inhibition by “Hexa + KI” mixture attributed to the formation of double layers adsorbed on the steel surface.