Microstructure and mechanical properties of hydroxyapatite obtained by gel-casting process

In the present work, well-shaped HAp green bodies were obtained by the gel-casting process with 50 vol.% slurry. After drying, the microstructure and pore distribution of the green body were investigated. The density, compressive strength and flexural strength of the green body were 1.621 g/cm(3), 32.6 +/- 3.2 MPa and 13.8 +/- 1.0 MPa, respectively. After pressureless sintering at the range of 1100-1300 degrees C for 2 h, the relative density of the final product ranges from 71.8 to 97.1% th. The maximum value of flexural strength, elastic modulus, hardness and fracture toughness were 84.6 +/- 12.6 MPa, 138 +/- 7 GPa, 4.45 +/- 0.18 GPa and 0.95 +/- 0.13 MPa m(1/2), respectively. SEM images show a compact and uniform microstructure; the average grain size was found by using the linear intercept method. XRD and FTIR determined the phase and the radical preserved after sintering. (c) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.