The Effect of Sintering Temperature on the Microstructural and Mechanical Characteristics of Hydroxyapatite Macroporous Scaffolds Prepared via Freeze-Casting
The most important characteristic of biomaterial as bone-repairing material, in addition to biocompatibility and appropriate porosity, is providing mechanical strength complying with injured tissue. In the present work, slurry with 15 vol% HA prepared from calcinated hydroxyapatite. The prepared slurry freeze casted unidirectionally with the cooling rate of 8°C/min from the ambient temperature. Then, green bodies freeze-dried for 72h following with sintering at different temperatures of 1250-1350°C with intervals of 25°C. The results showed that lamella space and porosity decreases with temperature while compressive strength and shrinkage goes up. Total porosity has a range of 75-83% while has a compressive strength of ~2-8 MPa. The sintered sample at 1350°C, with 75% porosity, which has a ~ 8 MPa compressive strength, chose to be the optimum. Also, some dendritic branch like structure and bridges can be seen on the internal walls of lamellae which can improve mechanical properties. These features may improve adhesion and growth of osseous cells.
Kunio Ishikawa and Yukihide Iwamoto
A. Zamanian et al., "The Effect of Sintering Temperature on the Microstructural and Mechanical Characteristics of Hydroxyapatite Macroporous Scaffolds Prepared via Freeze-Casting", Key Engineering Materials, Vols. 529-530, pp. 133-137, 2013