The Effect of Sintering Temperature on the Microstructural and Mechanical Characteristics of Hydroxyapatite Macroporous Scaffolds Prepared via Freeze-Casting


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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.



Key Engineering Materials (Volumes 529-530)

Main Theme:

Edited by:

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

Online since:

November 2012




[1] D. Sin et al., Polyurethane (PU) scaffolds prepared by solvent casting/particulate leaching (SCPL) combined with centrifugation, Mat. Sci. Eng. C, vol. 30, no. 1, pp.78-85, Jan. (2010).


[2] J. Wei et al., Preparation and characterization of bioactive mesoporous wollastonite - Polycaprolactone composite scaffold., Biomaterials, vol. 30, no. 6, pp.1080-8, Feb. (2009).


[3] C. Ji, N. Annabi, M. Hosseinkhani, S. Sivaloganathan, and F. Dehghani, Fabrication of poly-(DL)-lactide/polyethylene glycol scaffolds using the gas foaming technique., Acta biomaterialia, vol. 8, no. 2, pp.570-578, Sep. (2011).


[4] A. Salerno, S. Zeppetelli, E. D. Maio, S. Iannace, and P. a. Netti, Novel 3D porous multi-phase composite scaffolds based on PCL, thermoplastic zein and ha prepared via supercritical CO2 foaming for bone regeneration, Compos. Sci. Tech., vol. 70, no. 13, pp.1838-1846, Nov. (2010).


[5] C. K. Chua, K. F. Leong, K. H. Tan, F. E. Wiria, and C. M. Cheah, Development of tissue scaffolds using selective laser sintering of polyvinyl alcohol / hydroxyapatite biocomposite for craniofacial and joint defects, Design, vol. 5, pp.1113-1121, (2004).


[6] M. Schumacher, F. Uhl, R. Detsch, U. Deisinger, and G. Ziegler, Static and dynamic cultivation of bone marrow stromal cells on biphasic calcium phosphate scaffolds derived from an indirect rapid prototyping technique., J. Mater. Sci. -Mater. M., vol. 21, no. 11, pp.3039-48, Nov. (2010).


[7] S. Deville, E. Saiz, and A. P. Tomsia, Ice-templated porous alumina structures, Acta Materialia, vol. 55, no. 6, pp.1965-1974, Apr. (2007).


[8] S. Deville, E. Saiz, and A. P. Tomsia, Freeze casting of hydroxyapatite scaffolds for bone tissue engineering., Biomaterials, vol. 27, no. 32, pp.5480-9, Nov. (2006).


[9] H. Zhou and J. Lee, Nanoscale hydroxyapatite particles for bone tissue engineering., Acta biomaterialia, vol. 7, no. 7, pp.2769-81, Jul. (2011).


[10] Z. Sadeghian, J. G. Heinrich, and F. Moztarzadeh, Influence of powder pre-treatments and milling on dispersion ability of aqueous hydroxyapatite-based suspensions, Ceram. Int., vol. 32, no. 3, pp.331-337, Jan. (2006).


[11] J. Werner, B. Linner-Krčmar, W. Friess, P. Greil, Mechanical properties and in vitro cell compatibility of hydroxyapatite ceramics with graded pore structure, Biomaterials, vol. 23, pp.4285-4294, (2002).


[12] O. Prokopiev, I. Sevostianov, Dependence of the mechanical properties of sintered hydroxyapatite on the sintering temperature, Mater. Sci. Eng. A, vol. 431, pp.218-227, (2006).