ELECTROCHEMICAL AND SURFACE ANALYSIS STUDIES ON CORROSION INHIBTION OF CARBON STEEL

摘要

The corrosion inhibition of inhibitor Tris(hydroxymethyl)amino methane(THAM) and 1-hydroxyethylidenediphosphonic acid(HEDP) in combination with a bivalent cation like Zn 2+ in controlling corrosion of carbon steel immersed in aqueous solution containing 60 ppm Cl - was investigated using weight loss method and electrochemical impedance spectroscopy .The combined corrosion inhibition efficiency offered by 50 ppm of THAM, 250 ppm of HEDP, 50 ppm of Zn 2+ has 86%. The synergistic effect of the inhibiting compound was calculated. The corrosion inhibition was observed due to the formation of more stable and compact protective film on the metal surface. Fluorescence spectral analysis was used in detecting the presence of iron-inhibitor complex and the coordination sites of the metal inhibitor with iron were determined by the FTIR spectra. The surface morphology of the protective film on the metal surface was characterized by using Scanning Electron Microscope (SEM).