Helsinki University of Technology KURT SCHWABE CORROSION SYMPOSIUM 2004 4th Kurt Schwabe Corrosion Symposium Mechanisms of Corrosion and Corrosion Prevention June 13 - 17, 2004, Helsinki University of Technology, Espoo, Finland SPECTROSCOPIC, MICROSCOPIC AND ELECTROCHEMICAL STUDIES OF ADHESION PROMOTING THIN LAYERS AT POLYMER/METAL INTERFACES G. Grundmeier *,a , N. Fink * , C. Stromberg and B. Wilson * * Christian-Doppler Laboratory for Polymer-Metal Interfaces, Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40237 Düsseldorf, Germany a grundmeier@mpie.de Keywords: FT-IRRAS, Surface Electrochemistry, SKPFM, AFM, Conversion layer Introduction The development of environmental friendly conversion layers for both architectural and automotive applications has been the subject of increased research over the last decade as an alternative to carcinogenic chromate. Our aim was the study of chromate-free adhesion promoting thin layers on the surface of zinc coated steel in an effort to establish the interfacial reactions that are taking place and allow for improved chemistries to be implemented. Several techniques were used to get detailed information about the reaction states. FT-IRRAS and XPS were used to determine the effect both of cleaning on the pre-existing surface and the thickness of the layers produced after conversion treatment. In addition, SEM (in μm scale) and AFM (in nm scale) have been used to ascertain the impact that such treatments have on the microscopic surface roughness of the samples. Electrochemical methods (cyclovoltammograms, SKP and SKPFM respectively) have been used to investigate the chemistry occurring during the conversion process and to demonstrate the effectiveness of the new conversion layers at preventing delamination. Experimental Thin films of conversion layer were deposited on to model substrates like polished pure zinc (>99.95% Purity, Goodfellow, UK) and non-skin passed hot dip galvanized (HDG) steel supplied by voestalpine (Linz, Austria). Samples with a size of 30 mm x 30 mm were cut from the supplied substrate and subjected to a solvent cleaning process to ensure complete removal of any oils or surface contamination. In addition, alkaline cleaning of the surface (pH 13, 55°C) was carried out to activate the surface for the subsequent conversion layer treatment that was based on either phosphate or H 2 ZrF 6 chemistries.