Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-981-C7-985
Characterization of oxyde films and conversion layers on aluminium alloysJ. DE LAET, G. GOEMINNE, H. TERRYN and J. VEREECKEN
Vrije Universiteit Brussel, Dept. Metallurgy, Electrochemistry and Materials Science, Pleinlaan 2, 1050 Brussels, Belgium
Corrosion resistance and specific functional properties (dielectrical and decorative properties, adhesion, wear resistance) of aluminium alloys can be improved by surface treatments as electrochemical or chemical conversion reaction. The purpose of this study is to discuss the applicability of spectroscopic ellipsometry (SE) and electrochemical impedance spectrometry (EIS) for the characterization of the obtained conversion surface layers. It can be concluded that SE yields an accurate characterization for the thickness and the interfacial properties of both the barrier an porous oxide layer. The EIS allows to measure and to determine the sealing grade of the porous layer. These two complementary techniques can be used to investigate the growth mechanism of phosphate chromate conversion layers.
© EDP Sciences 1993