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 laborato ry containing different hetero atoms and substituents in the organic s tructures on hydrogen permeation and corrosion inhibition of mild stee l in acidic solutions has been studied using weight loss and various e lectrochemical AC and DC corrosion monitoring techniques. All the tria zole derivatives inhibit the corrosion of mild steel more effectively both in 1 N H2SO4 and 1 NHCl even at very low concentrations. Potentio dynamic polarisation studies clearly reveal that they behave predomina ntly as cathodic inhibitors. The extent of reduction of hydrogen perme ation current through steel surface has been studied by the hydrogen e lectropermeation technique. Double layer capacitance and charge transf er 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 inh ibition of corrosion.