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 (Ca5(PO4)2SiO4) 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 Ca3(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 °C/2 h and subsequent annealing at 1400 °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.