Characterization of micro-arc ceramic coatings on Ti-2Al-2.5Zr alloy substrates

Titanium oxide coatings were synthesized on Ti-2Al-2.5Zr alloy substrates by micro-arc oxidation (MAO) technique. The surface features of the coatings were studied by scanning electron microscopy. The micro-arc discharge channels of the Ti-2Al-2.5Zr alloy decrease while the discharge channel size increases clearly with an increase in treating time. With an increase of the coating thickness the porous layer thickness increases apparently. Phase composition of the surface layers of the coatings was evaluated by X-ray diffraction and X-ray photoelectron spectroscopy. The results of XRD and XPS analysis show that the MAO coating mainly consists of anatase and rutile TiO2.