| Hydroxyapatite [Ca10(PO4)6(OH)2, HA] exhibits excellent bio-activity property as bioceramic material. However, the brittleness of HA restricts it as a load-bearing bone replacement materials. Owing to titanium and titanium alloy as the traditional implant materials with excellent mechanical properties, preparation of HA coating based on titanium has become a hotspot of research in the field of bioceramic material.Three types of HA composite coating (organic, polymeric and inorganic compound) were deposited on titanium substrate used pore producer such as glucose, starch, chitosan by electrophoretic deposition and then the porous HA coating was obtained by sintering treatment process. The chemical composition, surface morphology, phase composition, and thermal stability of the porous HA coating were characterized by FT-IR, SEM, XRD and TG respectively. The bonding strength between the coating and substrate was tested by a shear strength testing experiment, the bio-activity of the coating was determined by immersion in simulated body fluid (SBF). The corrosive resistances were measured by CHI 660C electrochemical analysis in SBF too.The results show that the porous HA coating was obtained by sintering at 700℃, with pore diameter about 2-30μm and bonding strength up to 19.6 MPa. The coating surface was covered by carbonate-apatite after immersion in 1.5 times ion concentration of SBF (1.5SBF) for 5 days, indicating that the coating possesses a good bio-activity on its surface. Tafel curve and electrochemical impedance indicate that the corrosive resistance of porous HA coating is superior to pure titanium substrate. |
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