Electron beam currents of a few nanoamperes, currently used in nanometer scale scanning Auger/electron microscopy, induces severe oxidation of Al-Mg alloy surfaces at room temperature, Auger peak-to-peak oxygen curves for Al-Mg surfaces support the hypothesis that the electron beam creates additional nucleation sites for oxidation, However, the oxygen curves are described with a more complex functional form than that of single element oxidation investigated in the past, The e-beam oxidizes mainly the Al on areas where Mg is in solid Solution, while on areas where the Al3Mg2 phase is present a complex oxidation process takes place. In this case, besides Al oxidation also Mg oxidizes on the surface accompanied by Mg segregation through the surface oxide layer. (C) 2002 Elsevier Science B.V. All rights reserved.