Galvanostatic Polarisation and Polarisation Resistance Studies of Acid Corrosion of Commercial Copper in the Presence of some Heterocyclic Compounds

The inhibitive effect of pyridine, pyrrole, furan and thiophene on the corrosion of commercial copper in hydrochloric acid was studied by galvanostatic polarisation and polarisation resistance methods. The adsorbability of inhibitor was found to be dependent on both polarizability of hetero atoms and the tendency to donate π-electrons to the metal surface. Pyridine, furan and thiophene do not cause any considerable reduction of metal dissolution. Pyrrole shows mild inhibitive effect at low concentrations and considerable inhibition is however exhibited when present at high concentration in which a polymeric coating of pyrrole molecules perhaps blankets the metal surface. Inhibition efficiency decreases with temperature.