Generation of microstructures on a Ti–6Al–4V substrate through anodization

• This article shows influence of phases α and β of Ti–6Al–4V during anodization.
• A 3D-printed microcell was used for studying high voltage anodization.
• Between 70 V and 103 V the oxide layer grows faster on the β-phase (~ 120 nm).
• Between 104 V and 200 V dielectric rupture masks influence of the phases in the growth.
• Dielectric rupture contributes to a phase transformation anatase–rutile.

In this article, the influence of crystal structures of multiphase electrodes during a high voltage anodization process was demonstrated. The experimental was performed using a 3D-printed microcell and the investigated material was Ti–6Al–4V (α + β). The results showed that, for a limited range of potential (70 V to 103 V), atomic diffusion in β-phase was higher than in α-phase. Consequently, the growth of the oxide layer was not uniform. β-Phase generally grew 120 nm more than α-phase. An increase of voltage induced dielectric rupture, which produced uniform porous structures. This dielectric rupture also contributed to the oxide phase transformation (e.g. anatase to rutile).