High thermally stable Mg-substituted tricalcium phosphate via precipitation

Tricalcium phosphates incorporating small amounts of Mg show attractive biological performances in terms of enhanced bone apposition, bone in-growth and cell-mediated degradation. A systematic investigation on Mg-stabilized b-TCP (b-tricalcium phosphate, b-Ca3(PO4)2) is presented. Microstructure, composition and thermal behaviour were investigated by means of thermogravimetry and differential thermal analysis (TG-DTA), induced coupled plasma-atomic emission spectroscopy (ICP-AES), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption isotherms, Xray diffraction (XRD and HT-XRD), and scanning electron microscopy (SEM). Pure and Mg-substituted tricalcium phosphate precursors consisted of calcium-deficient hydroxyapatite, the specific surface area being 128 m2/g and 87 m2/g, respectively. Tricalcium phosphate nanostructured powders were obtained by thermal treatment above 800 8C. The incorporation of Mg within the calcium phosphate lattice promoted the formation of the b-TCP phase at slightly lower temperature and resulted in the stabilization of the b-polymorph at high temperature (i.e. 1600 8C).