A strategy using the sucrose evaporation technique for producing highly macroporous ceramic scaffolds with magnesium (Mg)-doped multiphasic or biphasic calcium phosphates was proposed. X-ray diffraction was performed to identify the ceramic phases, and thermogravimetric analysis and simultaneous differential scanning calorimetry (TGA/DSC) were used to analyze thermal behavior under different sintering temperatures. Product compositions with Ca/P molar ratios between 1.5 and 1.67 were synthesized and thermally treated up to 1050-1400 degrees C. Results showed that controlling the sintering temperature enabled various adjustable biphasic and multiphasic calcium phosphates to be prepared. Hydroxyapatite (HA) was obtained by increasing the sintering temperature of the reactants with sucrose and multiphasic a-tricalcium phosphates (TCP) and beta-TCP were stabilized by the addition of MgO. The spaces occupied by the sucrose (similar to 200 mu m) produced non-uniform pores after sucrose vaporized. These pores had dimensions ranging from several micrometers to hundreds of micrometers in the final fabricated scaffolds with an interconnected network. Considering phase decomposition and transfer into TCP, the phase amount and grain size of HA decreased with increased sintering temperature. Calculation of the Arrhenius equation revealed that the grain size with Mg doping was relatively larger and had reduced activation energy and smaller exothermic enthalpy, indicating that the formation of beta-TCP was stabilized by the MgO additive.

Keywords: Tricalcium phosphate; Hydroxyapatite; Porous scaffolds; Activation energy