Zinc-rich paints (ZRP) are one of the most effective coatings used in order to protect steel from corrosion and they have been studied in many aggressive media like sea water, marine and industrial environments. A major drawback of classic solvent-based paint is the emission of volatile organic compounds (VOC), which contribute to atmospheric pollution. Since the 1970s, powder coatings are often preferred, because they are only composed of dry thermosetting powders without organic solvent so they abide by environmental standards. In this work, three single-coat zinc-rich powder coatings were immersed in artificial sea water. These formulations are epoxy-based and contain a complex mixture of zinc dust which represents 50 or 70 wt.%. This zinc concentration is well below the one usually reported with liquid ZRPs and, for the third formulation, conductive pigments (carbon blacks) were added. Their electrochemical behaviors were compared, using electrochemical impedance spectroscopy (EIS) and micro-Raman spectroscopy. It was found that porosity and electrochemical behavior are intimately related to the conductive pigment presence in the coating. For two of the three formulations tested, EIS spectra can be explained with classical models. A contrario, the third one behaves differently and a transmission line model (modified de Levie's type) was used to account for all contributions. (C) 2004 Elsevier Ltd. All rights reserved.