Investigating the Effect of the Magnesium Fluoride Addition on the Mechanical Properties of Tricalcium Phosphate-Titanium Dioxide Composites for Biomedical Application

Tricalcium phosphate-Titanium dioxide-Magnesium fluoride composites were studied with regard to their densification, microstructure and mechanical properties. The performances of tricalcium phosphate - 40 wt% titanium dioxide composites were examined in relation to the effect of magnesium fluoride addition. By using the Brazilian test and Vickers indentation, the mechanical properties were evaluated. The mechanical properties of the TCP-40 wt% TiO2 composites were optimal after the sintering process at 1200 ℃ for 1 h and with 4wt% MgF2 addition. As a result, both rupture strength and Vickers hardness attained their highest values: 27 MPa and 360 HV, respectively. Consequently, adding 4 wt% MgF2 enriched Vickers hardness of the TCP - 40 wt% TiO2 composites about 270 HV. The obtained value (H = 360 HV) is very close to that of the enamel. Thus, scanning electron microscopy analysis has shown both the liquid phase formation and the presence of a novel lamella form referred to Mg2(PO4)F phase responsible of the significant enhancement of the composite’s mechanical properties. Beyond 4 wt% magnesium fluoride addition, dissolution–precipitation reaction occurred and caused simultaneously the excessive grain growth and the bubble formation. This reaction hindered the mechanical performances of the composites.