Nurses A-Phase: Synthesis and Characterization in the Binary System Ca2SiO4-Ca3(PO4)2

In the present study, a new single phase Si-Ca-P-based ceramic was obtained by conventional sintering of compacted mixtures of calcium hydrogen phosphate anhydrous, calcium carbonate, and silicon oxide. The synthesis conditions were the followings: heated up to 1550 degrees C for a total period of time of 72h (3d), with quenching in liquid nitrogen, milling, pressing, and reheating every 24h. Second, heating at 1300 degrees C/3h and subsequent annealed at 1200 degrees C/24h. Mineralogical and microstructural characterization of the obtained Si-Ca-P-based material was determined by Differential Thermal Analysis, X-ray diffraction, Scanning Electron Microscopy with attached wavelength dispersive spectroscopy, Micro-Raman and Fourier Transform Infrared Spectrometer. The results showed a single Si-Ca-P phase material with a Ca2SiO4/Ca-3(PO4)(2) molar ratio equal to 2:1. The parameters of the Weibull distribution of strength, determined by diametrical compression of disks, were: modulus, m=13, and characteristic strength sigma(0)=0.60MPa.