Revising the Subsystem Nurse's A-Phase-Silicocarnotite within the System Ca3(PO4)2-Ca2SiO4

The subsystem Nurse's A-phase-silicocarnotite within the system Ca-3(PO4)(2)-Ca2SiO4 was conducted as a preliminary step toward obtaining new biomaterials with controlled microstructures. Phase composition of the resulting ceramics was studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy with attached wavelength dispersive spectroscopy. The results showed that the sub-system presents an invariant eutectoid point at 1366 +/- 4 degrees C with a composition of 59.5 wt % Ca-3(PO4)(2) and 40.5 wt % Ca2SiO4, and typical eutectoid microstructure of lamellae morphology. These results are in disagreement with the previous reported data, which locate the invariant eutectoid point at 1250 +/- 20 degrees C with a composition of 55 wt % Ca-3(PO4)(2) and 45 wt % Ca2SiO4. In addition, cell attachment testing showed that the new eutectoid material supported the mesenchymal stem cell adhesion and spreading, and the cells established close contact with the ceramic after 28 days of culture. These findings indicate that the new ceramic material with eutectoid microstructure of lamellae morphology possesses good bioactivity and biocompatibility and might be a promising bone implant material.