Effect of sintering on the properties of magnesium doped-biphasic calcium phosphate (Mg-BCP)

Magnesium doped-biphasic calcium phosphate (Mg-BCP) powder was successfully synthesized via an aqueous precipitation method at room temperature. Calcium nitrate tetrahydrate (Ca(NO3)2.4H2O), di-ammonium hydrogen phosphate ((NH4)2HPO4), and magnesium nitrate hexahydrate (Mg(NO3)2. 6H2O) are the precursors involved. Mg-BCP powder was pressed into pallet form and sintered at three different temperatures (900 °C, 1100 °C, and 1200 °C). The sintered Mg-BCP pellet had been characterized via apparent porosity and bulk density measurement, Vickers hardness test, and Field Emission Scanning Electron Microscopy (FESEM). From the analysis, the 1200 °C sintered Mg-BCP pellet (M12) has the lowest apparent porosity and the highest bulk density. It shows that a higher sintering temperature may affect the increasing grain growth of the Mg-BCP pellet. However, the crack can easily propagate inside the bigger grain of M12 and thus gives a low hardness value. Moreover, the 900 °C sintered Mg-BCP pellet (M9) has the lowest hardness value due to high porosity along with a partially formed grain.