Abstract: The adsorption behavior of imidazoline amide as a cationic inhibitor for inhibiting galvanic corrosion has been investigated by using electrochemical methods and atomic force microscopy (AFM) technology. The results show that the adsorption behavior of the inhibitor is significantly affected by the excess charge on the metal surface. Carbon steel and stainless steel carry negative and positive excess charges when they are immersed in 1% NaCl solution, respectively. The inhibitor adsorbs on the surface of carbon steel, while it does not adsorb on the surface of stainless steel in aqueous NaCl solution. When the two metals are electrically coupled in NaCl solution, positive and negative excess charges are carried on the carbon steel and the stainless steel, respectively. The inhibitor can adsorb on the surfaces of both carbon steel and stainless steel. However, in this case, the surface coverage of the inhibitor film formed on the carbon steel decreases compared with that on the surface of single carbon steel, and the adsorbability of the inhibitor on the surface of carbon steel is weakened.

Key words: Atomic force microscopy, Electrochemical method, Adsorption behavior, Surface excess charge, Inhibitor, Galvanic corrosion