THE EFFECT OF MOLECULAR-STRUCTURE ON HYDROGEN PERMEATION AND THE CORROSION INHIBITION OF MILD-STEEL IN ACIDIC SOLUTIONS

The influence of some triazole derivatives synthesised in the laboratory containing different hetero atoms and substituents in the organic structures on hydrogen permeation and corrosion inhibition of mild steel in acidic solutions has been studied using weight loss and various electrochemical AC and DC corrosion monitoring techniques. All the triazole derivatives inhibit the corrosion of mild steel more effectively both in 1 N H2SO4 and 1 NHCl even at very low concentrations. Potentiodynamic polarisation studies clearly reveal that they behave predominantly as cathodic inhibitors. The extent of reduction of hydrogen permeation current through steel surface has been studied by the hydrogen electropermeation technique. Double layer capacitance and charge transfer resistance values were derived from Nyquist plots obtained from AC impedance studies. The adsorption of these compounds on steel surface from both the acids obeys the Temkin adsorption isotherm. UV spectral studies were also carried out to establish the actual mechanism of inhibition of corrosion.