Imaging XPS investigation of the lateral distribution of copper inclusions at the abraded surface of 2024T3 aluminium alloy and adsorption of decyl phosphonic acid

The XPS images of copper-rich intermetallic particles in an aluminium alloy have been obtained after argon ion removal of the oxide at the surface of mechanically polished 2024T3 alloy. Comparison of the XPS analysis before and after etching indicates that the oxide does not include significant concentrations of copper. Through analogy with copper incorporation into anodic films, it is proposed that incorporation into the oxide would only occur after preferential oxidation of aluminium and enrichment of copper immediately below the oxide film. Self-assembling monolayers of decyl phosphonic acid (DPA) have been adsorbed to the surface of 2024T3 alloy and superpure Al. The lateral distribution was mapped with XPS using the characteristic P 2s signal. The distribution of DPA was relatively uniform on both MS-Al and 2024T3. This is consistent with the model of the alloy surface constructed from the imaging XPS analysis, which suggests that the oxide on the large particles is dose in composition to that on to the surrounding matrix. Copyright © 2002 John Wiley & Sons, Ltd.