Single-phase silicocarnotite synthesis in the subsystem Ca3(PO4)2-Ca2SiO4

In the last years, the addition of silicon to hydroxyapatite and tricalcium-phosphate materials is being widely studied, due to the well-known influence of silicon on bone formation. Silicocarnotite (Ca-5(PO4)(2)SiO4) presents a structure type carnotite, very close to hydroxyapatite, with a wide range of Ca2+, SiO44- and PO43- solid solutions. These characteristics make silicocarnotite attractive as potential biomaterial. In this work, the synthesis of silicocarnotite has been studied by a simple and economical method. The formulation and thermal treatment have been designed based on the information supplied by the Ca-3(PO4)(2)-Ca2SiO4 phase diagram. Single-phase silicocarnotite material has been obtained from stoichiometric mixtures of tricalcium phosphate and dicalcium silicate. In order to optimize the synthesis conditions, a two-stage heating was used: heating at 1550 degrees C/2 h and subsequent annealing at 1400 degrees C/4 h. Mineralogical and microstructural characterizations of the obtained material have been determined by X-Ray Diffraction, Fourier Transform Infrared Spectrometry Attenuated Total Reflection and Micro-Raman and Scanning electron microscopy. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.