Influence of experimental parameters on spatial phase distribution in as-sprayed and incubated hydroxyapatite coatings
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In the present study, the behavior and properties of plasma-sprayed hydroxyapatite coatings [Ca10(PO4)6(OH)2, HAp] were investigated in relation to the spraying process. The experiments were focused on the influence of type of feedstock and spray power on the phase composition and distribution within the coatings. Depth profiles of the coatings were investigated before and after incubation in revised simulated body fluid (SBF) by X-ray diffraction and infrared spectroscopy. Besides HAp, the coatings contain oxyapatite (OAp) and carbonate apatite (CAp). Additionally, tricalcium phosphate (TCP), tetracalcium phosphate (TTCP), CaO, and an amorphous phase were detected in the coatings. The HAp content directly depends on the used spray powder and spray power, where the influence of spray powder is much higher than the influence of the spray power. The grain size range of the spray powder strongly influences the HAp content in the coating and the formation of CaO. The in vitro behavior of the coatings in simulated body fluid mainly depends on the contents of CaO and amorphous calcium phosphate, respectively. The formation of portlandite due to the reaction of the coating with the SBF is strongly influenced by the porosity of the coatings and can be used as an indicator for the depth of interaction between fluid and coating.
KeywordsSimulated Body Fluid Amorphous Calcium Phosphate TTCP Tetracalcium Phosphate Ti6Al4V Substrate
We thank David Rafaja and Gerhard Schreiber from the Institute for Materials Science for carrying out the XRD measurements with grazing incidence, Gert Schmidt, Bernd Ullrich and Ulf Kempe for the ESEM and REM analyses.
- 1.E. Wintermantel, S.-W. Ha, Medizintechnik mit biokompatiblen Werkstoffen und Verfahren. (Springer, Berlin, 2002)Google Scholar
- 2.K. De Groot, J. Ceram. Soc. Jpn. 99, 917–926 (1991)Google Scholar
- 7.L. Sun, C.C. Berndt, C.P. Grey, Mater. Sci. Eng. A360, 70–84 (2003)Google Scholar
- 10.R.B. Heimann, Plasma-spray Coating: Principles and Applications. (VCH, Weinheim, 1996)Google Scholar
- 13.Y.C. Tsui, C. Doyle, T.W. Clyne, Biomaterials 19, 2125–2029 (1998)Google Scholar
- 16.J.C. Elliott, Structure and Chemistry of the Apatites and Other Calcium Orthophosphates. Studies in Inorganic Chemistry, vol. 18. (Elsevier, Amsterdam, 1994)Google Scholar
- 17.J. Götze, H. Hildebrandt, R.B. Heimann, Biomaterialien 2, 54–60 (2001)Google Scholar