Apatite formation on porous titanium by alkali and heat-treatment

Hydroxyapatite coating on metal implants is an effective method to enhance bioactive properties of the metal surface. In the present study, the porous titanium with maximal pore size approximately 250 μm and 40% porosity was prepared by powder metallurgy process. All of samples were subjected to alkali and heat-treatments. The bone-like apatite coatings were formed on the surfaces of alkali- and heat-treated porous titanium while samples were soaked in simulated body fluid (SBF). Porous network structure was fabricated and sodium titanate and titanium oxide were formed on the surfaces after the porous titanium was subjected to NaOH aqueous solution. Apatite coatings were not induced in SBF when porous titanium was subjected to 0.5 or 1.0 M NaOH aqueous solutions because of the small porous network structure on the surfaces. The network structure was densified slightly and more uniform nucleation of apatite occurred on the surfaces of the alkali- and heat-treated porous titanium. It is expected that porous titanium with surface apatite coatings can be used in clinical orthopedics.