On the use of SKPFM for in situ studies of the repassivation of the native oxide film on aluminium in air

This work presents a novel procedure to study the growth of the surface native oxide film on metals in air, based on scanning Kelvin probe force microscopy. For reactive metals such as aluminium, when the native metal oxide is damaged, fast reformation of the oxide film occurs. The methodology presented here allows this oxide film reformation to be studied in situ. By monitoring the evolution of the Volta potential with time in a scratch on the sample's surface, the characteristic behavior of the oxidation of aluminium metal could be observed. The procedure was carried out on a pure aluminium sample, but could potentially be applied in other metals, provided that the relation between the oxide film and the Volta potential is established.