This paper deals with the characterization of an environment-friendly corrosion inhibitor formulated for industrial cutting fluids. Polarization measurements and electrochemical impedance spectroscopy (EIS) tests reveal the formation of a 3D film at the interface metal/elecrolyte. This film blocks iron ions oxidation by forming a barrier on the metallic surface. Studies concerning, respectively, inhibitor concentration, immersion time and temperature show that effects of these three parameters are strongly linked and influence considerably the protective effect of the inhibitor. XPS analyses confirm formation of an inhomogeneous layer submitted to a water-uptake with time when inhibitor is not added in necessary concentration. (C) 2005 Elsevier Ltd. All rights reserved.