SYNERGISTIC INFLUENCE OF IODIDE-IONS ON THE INHIBITION OF CORROSION OF MILD-STEEL IN SULFURIC-ACID BY CYCLOHEXYLAMINE

The synergistic inhibition of corrosion of mild steel in 0.5 M H2SO4 b y a combination of cyclohexylamine (CHA) and iodide ions has been stud ied using different electrochemical techniques. Corrosion inhibition i s found to decrease with increase in the concentration of CHA. Iodide ions are found to enhance the inhibition by CHA considerably. Synergis tic parameters such as SI and Se obtained from values of inhibition ef ficiency and surface coverage are found to be more than unity. This ob servation clearly shows the synergistic influence of iodide ions on th e corrosion inhibition by CHA. The adsorption of CHA alone and in comb ination with iodide ions obeys Langmuir's adsorption isotherm.