INVESTIGATION OF THE BEHAVIOR OF 5-MERCAPTO-1-PHENYL- TETRAZOLE AS AN INHIBITOR AGAINST COPPER CORROSION IN SULFURIC ACID MEDIA

摘要

The potential dependence of adsorption and kinetic properties of inhibitor film formation on a copper surface was studied in an acidic environment by using surface sensitive techniques: electrochemical quartz crystal microbalance (EQCM), and electrochemical scanning tunneling microscopy (EC-STM). The investigated inhibitor was 5-mercapto-1-phenyl-tetrazole (5-PhTT) in 1 mmol.dm~(-3) H_2SO_4. EQCM investigations were focused on the study of the electrode mass decrease in the absence and presence of 5-MPhTT at open circuit potential. The apparent mass and current variation as a function of the electrode potential was also registered. Results revealed that, the anodic current density and the electrode mass loss decreased due to the presence of 5-MPhTT in the solution. EC-STM has been employed to study the structure of the Cu (111) single crystal surface in the presence of 5-MPhTT. The EC-STM measurements showed copper dissolution in blank and inhibitor containing solutions and the surface morphology at various potential values. The molecular structure of 5-MPhTT adlayer was investigated. Our in-situ results were combined with quantum chemical calculations, which gave information on molecular size and symmetry.