Surface modification of biomedical tantalum by micro-arc oxidation

Tantalum (Ta) is well known for its excellent workability, fatigue resistance and fracture toughness. However, it does not show bone-bonding ability (i.e. bioactivity). In the present work, porous Ta-oxide films incorporating calcium (Ca) and phosphorus (P) were prepared on pure Ta by micro-arc oxidation (MAO) in an electrolyte containing calcium glycerophosphate and calcium acetate. Film morphology, composition and phase were investigated using scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction, respectively. The surface topography and roughness of the films were investigated by atomic force microscopy operated in tapping mode. The results showed that the surfaces of the coatings exhibited typical porous and rough structures typical of MAO. Ca and P were successfully incorporated into the MAO coatings, and their concentrations could be controlled by adjusting the MAO parameters. The formation of the MAO coatings endowed Ta with potential bioactivity, and the resulting films may be promising candidates for implants.