| Abstract: | The cathodic deposition of transition metals allows obtaining surface conditions similar to those found in alloys and to study the anodic processes occurring on them. In this work, some aspects dealing with the influence of the presence of electro-deposited particles on the growth of anodic oxide films at potentials lower than 10 V in neutral acetate buffer solution were analysed by conventional electrochemical techniques supported by SEM and TEM. At the first stages of anodization, the particles lose progressively their contact with the substrate due to the growth of the aluminium oxide film leaving a defective structure. Thus, at potentials higher than 0.9 V SSE, the electrical contact of particles is established by tunnelling through localized states generated by defects in the band-gap. This, in turn, leads to the formation of preferential conductive paths. Thus, the dissolution/passivation of particles and the evolution of oxygen on them at higher anodic potentials could be observed. At potentials higher than 4 V, defects are released towards the oxide/electrolyte interface and the behaviour of pure aluminium oxide is observed again. |
