The effect of titanium bead diameter of porous titanium on the formation of micro-arc oxidized TiO2-based coatings containing Si and Ca

Porous titanium was prepared by vacuum sintering titanium beads with diameters of 100, 200, 400 and 600 m m on titanium plate at temperature 1723 K for 2 h. Then TiO 2 -based coatings containing Si, Ca, Na (SCN) elements were fabricated by micro-arc oxidation (MAO) on the porous titanium. The results showed that the surface morphology, SCN concentrations and x-ray diffraction intensity of titania of the MAO coatings were significantly affected by titanium beads diameter. With increasing titanium beads diameter, the porosity of porous titanium raised gradually in a range of 26.5%–35% and the specific surface area of porous titanium decreased gradually in a range of 45%–5% mm 1 . The oxidizing ability is positive correlated with bead diameter as porosity but negative correlated with bead diameter as specific surface area. In this paper, the porosity and specific surface area are two key factors to influence the formation and microstructures of MAO coating