Synthesis and Synterability of Hydroxyapatite-Coated Zirconia Nanopowders
F. Bondioli, V. Cannillo, A.M. Ferrari and T. Manfredini
Università di Modena e Reggio Emilia, IT
Hydroxyapatite (HAP), Ca10(PO4)6(OH)2, is a well-known and a valuable implant material with biocompatibility and bioactive properties. Full utilisation of the unique properties of hydroxyapatite bulk ceramics is, however, possible only after its proper reinforcement, i.e. by preparation of composites. In zirconia reinforced hydroxyapatite composites (HAP-ZrO2) it is possible to combine extremely advantageous properties of both biomaterials, previously applied separately. The goal of this study was to synthesized a HAP-coated zirconia composite powder by the precipitation of HAP in presence of zirconia. The idea was to avoid uncontrolled agglomeration of the zirconia nanostructured reinforcement during the sintering step. ZrO2 nanopowders, previously synthesized by hydrothermal crystallisation, was added to the appropriate amount of an intensively stirred aqueous suspension of Ca(OH)2. HAP was precipitated by addition of H2PO4 at controlled pH in order to obtain 3, 5, 10, 15, 30 and 50 wt % zirconia reinforced composite powders. The obtained powders were fully characterized by TEM, quantitative X-ray diffraction analysis by Rietveld-R.I.R. and BET. The sinterability and the thermal behaviour were determined by High Temperature – XRD and thermal analysis (TG-DTA, mechanical and optical dilatometry) in order to define the optimal sinterisation conditions. The sintered materials were characterized in order to evaluate their structural, morphological and mechanical properties.
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Nanotech 2007 Conference Program Abstract