Synthesis and characterization of single-phase silicon-substituted α-tricalcium phosphate

Silicon-substituted calcium phosphate (CaP) powders with a Ca/(P+Si) ratio of 1.50 have been prepared by a wet chemical method, with silicon contents up to 2.16 weight percent (wt%). Sintering for 2 h at 1250 °C yields single-phase silicon-substituted alpha tricalcium phosphate (Si-α-TCP) for compositions between 0.59 and 1.14 wt% silicon. The sintered powders have been characterized with X-ray fluorescence (XRF) spectrometry, X-ray diffraction (XRD), attenuated total reflection infrared spectroscopy (ATR-IR) and transmission electron microscopy (TEM). Compositions with less than 0.59 wt% silicon result in mixtures of Si-α-TCP, β-TCP, and calcium hydroxyapatite (HA), while compositions with more than 1.14 wt% silicon result in mixtures of Si-α-TCP and HA. The lattice parameters of single-phase Si-α-TCP prepared with 0.87 wt% silicon are a=12.874(1)Å, b=27.372(2)Å, c=15.225(1)Å, and β=126.38(1)°β=126.38(1)°.