Synthesis of bioactive ceramic on the titanium substrate by micro-arc oxidation

Bioactive ceramic films on titanium substrate are prepared successfully by micro-arc oxidation in electrolyte solution containing NaOH only. The coatings are prepared by micro-arc oxidation at various applied current densities (200-400 mA/cm2) and in NaOH electrolyte with different concentrations. The XRD shows that they are composed of rutile, anatase, Na2Ti6O13, and Na2Ti4O9 phases. The composition and surface morphologies are strongly dependent on the applied current density and electrolyte concentration. For example, at high current density, the phase is mainly composed of rutile and Na2Ti6O13, and at high electrolyte concentration, it is Na2Ti6O13 phase. The morphologies of the samples vary with the increase of current and electrolyte concentration. The apatite-inducing ability of bioactive ceramic films is evaluated in biological model fluids. After soaking in biological model fluids, the titania-based coatings containing Na2Ti6O13 phase have excellent capability of inducing bone-like apatite.