Bioactivity of Titanium Coating

Vacuum plasma sprayed Ti coatings were chemically treated with 5.0mol/L NaOH at 40℃ for 24h and immersed into two kinds of simulated physiological solutions containing Ca2+, HPO42- ions. The surface morphologies and compositions of Ti coating before and after alkali treatment were examined by SEM and AES respectively. The formation layers on the Ti coating after immersion in FCS and SBF were characterized by SEM, EDS, XRD and FT-IR. The changes of ion concentration and pH value of FCS after immersion were measured by ICP-AES and pH meter. The results obtained indicate that the fibrous and net-like surface structure forms on the surface of porous Ti coating by treatment of NaOH solution which consists of Na, Ti and O element with the atom ratio nearly equal to that of Na2TiO3. After immersion in simulated physiological solutions, the treated Ti coating shows apatite-forming ability and the apatite formed in FCS is oriented crystallized, plate-like HA with trace of OCP whereas the apatite precipitated in SBF is needle-like carbonate-containing hydroxyapatite. The bioactivity of the alkali treated Ti coatings can be explained in terms of the formation of hydrated titanate which can induced apatite nucleation and growth in FCS and SBF.