Mechanical Properties of Biomaterials Based on Calcium Phosphates and Bioinert Oxides for Applications in Biomedicine - Advances in Biomaterials Science and Biomedical Applications - page 39

Figure 11. The SEM micrographs of the Al 2 O 3 -10 wt% TCP composites sintered for 1 hour at: (a) 1500°C, (b) 1550°C
and (c) 1600°C.

The results of the microstructural investigations of Al 2 O 3 -10 wt% TCP composites sintered at
1600°C for different lengths of time (0 min, 30 min, 60 min and 90 min) are shown in Figure
12. These micrographs reveal the influence of different lengths of time on the microstructur‐
al developments during the sintering process at 1600°C. The microstructure of the samples
leads to the formation of important cracks of different sizes with composites sintered for 0
min, 30 min and 90 min (Figure 12 ba-b and 12d). The continuous phases are relative to the
β-TCP phase while the grains of a small size are relative to the alumina phase (Figure 12 ba-
b and 12d). In Figure 12c, we notice the coalescence between the grains after the sintering
process for 60 min confirming the best mechanical resistance in these conditions.

Furthermore, the sintering behavior of the Al 2 O 3 -TCP composites has been studied relative
to the β-TCP content. It has been shown that alumina should be used in order to prevent the
β-α transition of the tricalcium phosphate during the sintering process. At any rate, the re‐
sults obtained in the present work would be valuable in the performance of Al 2 O 3 - TCP
composites resembling bone tissue engineering (Table 3). In fact, our preliminary tests indi‐
cated that the rupture strength of Al 2 O 3 -TCP composites is from 2 to 14 MPa. The optimum
value of the Al 2 O 3 - 10 wt% TCP composites sintered at 1600°C for one hour reached 13.5