Use of a biopolymer as corrosion inhibitor on carbon steel: afm and electrochemical techniques in simulated interstitial concrete electrolyte

摘要

This work presents the evaluation of a composition containing a biopolymer as a corrosion inhibitor. The compositions was used in alkaline solutions (Ca(OH)_2 satd.) simulating the pH at the interstitial concrete electrolyte medium. Corrosion studies were performed by potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). Tafel polarization curves for carbon steel in Ca(OH)_2 in absence and presence of biopolymer showed that the presence of the inhibitors promotes a decrease in both anodic and cathodic current densities and a slight shift of E_(corr) in the anodic direction. Polarization curves showed that the inhibitors are mixed-type inhibitors in alkaline medium. Its efficiency is above 65% and inhibition efficiency increased with increasing concentration of biopolymer. The atomic force microscopy (AFM) images were obtained in contact mode and reveal that the biopolymer caused a very significant statistical decrease on roughness of the carbon steel surface.