Abstract The oxidation of aluminum by electron bombardment of a water-covered surface at 90 K has been investigated by XPS, EELS and high-resolution electron energy-loss spectroscopy. Electron bombardment converts the adsorbed ice layer into a disordered aluminum oxide film with very high efficiency. The cross-section for water conversion is 2.5×10 −16 cm 2 for an electron energy of 100 eV. The threshold energy of the electronic stimulation has been estimated to be 6±1 eV. The excitation probably proceeds via direct electron attachment, leading to dissociative production of an OH radical species, which is very effective for surface oxidation.