CaFap-Alumina Composite Bioceramics Based on the New CaAlO₂F Phase

We report on the synthesis of a new CaAlO₂F phase with a perovskite-type structure, which was formed as a third phase in the CaFap-alumina composite during the calcination of a mixture of Ca₁₀(PO₄)₆F₂ and Al(OH)₃. The atomic coordinates, lattice constant, and space symmetry group of the CaAlO₂F phase were determined by the XRD method. Next, the chemical composition and mechanical properties of the CaFap-alumina composite bioceramics were investigated. The material was found to exhibit high porosity, with pore diameters ranging from 100 to 1000 μm. The measured mean values of microhardness and Young's modulus were 6.1 ± 1.0 GPa and 103 ± 8 GPa, respectively. The new CaAlO₂F phase constituting the bioceramics exhibited a significantly higher nanohardness of 11.8 ± 1.5 GPa and Young's modulus of 137 ± 9 GPa, which indicates that this phase can significantly improve the mechanical properties of CaFap-alumina bioceramics. The resulting fluorapatite-based biocomposite can pave the way for advanced medical ceramics as a material for load-bearing implants.