Zinc and iron substrates were coated with polyester acrylate films. The samples were cured by an exposure to different doses of ultraviolet (UV) radiation energy at different radiant fluxes of the UV light source. Infrared spectroscopy was used to estimate the resulting degree of macromolecular cross-linking. Its effect on the barrier properties of the coating was investigated by Electrochemical Impedance Spectroscopy (EIS). A reduced water uptake and a reduced swelling of the coating as well as a decelerated diffusion of water through the polymer bulk were detected on polyester acrylate coated zinc samples that were exposed to increasing UV energy doses at low UV light intensity. With the Scanning Kelvin Probe (SKP), a similar tendency was detected for the resistance of polyester acrylate/iron oxide/iron interfaces against cathodic delamination. In contrast, curing with large energy doses at high UV intensity led to decelerated ion transport kinetics along the interface, but did not further improve the barrier properties of the coating. This indicated that SKP data gained on Fe substrates and EIS data recorded on Zn substrates can be correlated if UV curing does not result in strong tension within the polyester acrylate films. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3575634] All rights reserved.