AFM and FTIR studies of organic cation adsorption on carbon steel coupled with stainless steel

Abstract

The electrochemical behavior of the anode of the galvanic couple and the adsorption behavior of the cationic inhibitor on it have been investigated by using electrochemical methods, atomic force microscopy (AFM) and infrared spectroscopy (FTIR) technology. A galvanic electrode was prepared by coupling N80 carbon steel (CS) and S31803 stainless steel. All experiments were performed in NaCl solution in the presence or absence of an inhibitor. The results show that, in aqueous NaCl solution, CS carries negative excess charge, for the couple, positive charge is carried on the CS side (anode). The adsorption behavior of the cationic inhibitor on CS is significantly affected by the excess charge carried on it. Owing to the charge interaction between electrodes and the cationic inhibitor, the inhibitor has a greater tendency to adsorb on the single CS and less tendency to adsorb on the CS of the couple. Because of this, the adsorption film on the anode (CS side) of the couple is thin and defective. The failure of inhibiting galvanic corrosion attributes to the defective protective layer formed on the anodic area. Copyright © 2006 John Wiley & Sons, Ltd.