Characterisation of calcium phosphate/titanium dioxide hybrid coatings
- First Online:
- Cite this article as:
- Boyd, A.R., Burke, G.A., Duffy, H. et al. J Mater Sci: Mater Med (2008) 19: 485. doi:10.1007/s10856-006-0031-z
The role of titanium dioxide (TiO2) as a means to engender enhanced stability into calcium phosphate (Ca-P) coatings has been well recognised. Several different methods have been used to create such Ca-P/TiO2 hybrid layers on a range of substrates. This paper reports the properties of a Ca-P/TiO2 system created by the sputter deposition of hydroxyapatite onto a titanium surface and the subsequent thermal diffusion of TiO2 through the porous Ca-P layer. The role of temperature in determining the surface contribution from TiO2 has been determined. Coatings annealed up to 600 °C did not exhibit any hybrid nature in the uppermost surface, however the coatings annealed to 700 °C did show the presence of both HA and rutile TiO2. The surfaces annealed to 800 °C were predominantly rutile TiO2. It was also observed that the Ca/P ratio decreased with increasing annealing temperature and that the coating annealed to 700 °C had a value of 1.82 ± 0.07, which was closest to stoichiometric HA. Furthermore, the coatings that were annealed to 700 °C displayed a Ca-P/TiO2 hybrid nature, specifically in their uppermost surface and supported the growth and proliferation of osteoblast-like cells more readily when compared to the HA coatings or the rutile TiO2 surfaces.