Influence of the sintering temperature on Young's modulus and the shear modulus of tricalcium phosphate - fluorapatite composites evaluated by ultrasound techniques

The mechanical properties of the tricalcium phosphate sintered between 1100 degrees C and 1450 degrees C for 1 h with different percentages of fluorapatite (13.26 wt%; 19.9 wt%; 26.52 wt%; 33.16 wt% and 40 wt%) have been characterized and evaluated using the ultrasound techniques. Young's modulus and the shear modulus were calculated from the point of the longitudinal and the transversal ultrasonic velocities. Young's modulus and the shear modulus of tricalcium phosphate increased with the sintering temperature and with the addition of the fluorapatite additive into the tricalcium phosphate matrix. At 1300 degrees C, the shear modulus and Young's modulus of the tricalcium phosphate - 40 wt% fluorapatite composites registered optimum values: 26 GPa and 66.2 GPa, respectively. Above 1300 degrees C, the mechanical properties of the tricalcium phosphate - fluorapatite composites were hindered by the tricalcium phosphate allotropic transformation and the formation of both the intragranular porosity and the cracks. (c) 2013 Elsevier B.V. All rights reserved.