Preparation of β-tricalcium phosphate from precursors obtained by a wet precipitation method [articol]

Abstract

Calcium phosphate ceramics are widely used as bone replacements in the field of oral and plastic surgery. Among these, hydroxyapatite and β-tricalcium phosphate favor bone reconstruction, due to high properties of resorbability for β-Ca₃(PO₄)₂ and good osteoconductivity for hydroxyapatite. In this paper we present the preparation of β-tricalcium phosphate Ca₃(PO₄)₂ by thermal treatment of a calcium deficient hydroxyapatite. The hydroxyapatite was prepared by wet precipitation of Ca(II) with (NH₄)₂HPO₄, starting from two calcium salts: calcium nitrate Ca(NO₃)₂ and calcium acetate Ca(CH₃COO)₂. The precipitation reaction products were characterized by FT-IR spectrometry, XRD analysis and thermal analysis. These techniques confirmed the formation of the calcium deficient hydroxyapatite, for both Ca(II) precursors. The products of the hydroxyapatites annealed at 800°C and 1000°C contained β-Ca₃(PO₄)₂ as single crystalline phase.