Interfacial mixing and improved adhesion have been proposed advantages of ion-beam-assisted film deposition (IBAD) techniques, however, very little information is available on the barrier properties of these films. This study has employed electrochemical impedance and open-circuit potential measurements to examine the barrier characteristics of such films. Thin (ca. 150A) films were formed on steel by impacting a 30 keV ion beam of either H, He, Ne, C2F6, or C2H6 into butadiene gas held in front of the substrate. These films were comPared to thin (3 ~m) films of conventional coatings: Epon 828, Epon 815, polyurethane} and vinyl XYHL. IBAD films appear to be limited by pinhole defects possibly associated with inclusions and precipitates at the substrate surface. The changes in the impedance spectra of ion-beam-assisted films show a correlation to the efficiency of energy transfer from the ion beam to the film species. This in turn has been correlated with interfacial mixing and adhesion characteristics. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 142.104.240.194 Downloaded on 2015-06-04 to IP