Influence of magnesium doping on the phase transformation temperature of β-TCP ceramics examined by Rietveld refinement

The influence of Mg doping in Ca 3(PO 4) 2 on the transformation temperature of β-tricalcium phosphate ( β-TCP) to α-tricalcium phosphate ( α-TCP) was examined. A maximum substitution by 14 mol% of Mg 2+ on Ca 2+ sites in the β-TCP structure was determined for powders calcinated at 1025±10 °C. X-ray powder diffraction analysis (XRPD) in combination with Rietveld method (TOPAS 2.1) was employed for quantitative phase analysis and structural refinement. The synthesized and characterized Mg-doped samples were sintered in air atmosphere in a vertical tube furnace at suitable temperatures ranging from 1460 to 1680 °C and subsequently quenched to room temperature, in order to stabilize α-TCP. The β to α transformation temperatures were determined by differential temperature analysis and XRPD analysis.