Abstract

TiO_2 was successfully formed on a Ti specimen by MAO (Micro-Arc-Oxidation) method treated in Na_3PO_4 electrolyte. This study deals with the influence of voltage and working time on the change of surface microstructure and phase composition. Voltage affected the forming rate of the oxidized layer and surface microstructure where, a low voltage led to a high surface roughness, more holes and a thin oxidized layer. On the other hand, a high voltage led to more dense surface structure, wider surface holes, a thick layer and fewer holes. Higher voltage increases photocatalytic activity because of better crystallization of the oxidized layer and good phase composition with anatase and rutile TiO_2, which is able to effectively separate excited electrons and holes at the surface.

• Keywords: Titanium;Surface oxidation;MAO(Micro-Arc-Oxidation);Photocatalytic activity;