Consolidation of Nanocrystalline Hydroxyapatite Powder

Iis Sopyan
Department of Manufacturing and Materials Engineering, Faculty of Engineering, International Islamic University Malaysia

Chou Yong Tan
Department of Engineering Design & Manufacture, University Malaya, Malaysia

S. Ramesh
Ceramics Tech. Lab., University Tenaga Nasional, Malaysia

M. Hamdi
Department of Engineering Design & Manufacture, University Malaya, Malaysia

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     Last modified: March 29, 2006

Abstract
The effect of sintering temperature on the sinterability of synthesized nanocrystalline hydroxyapatite (HA) was investigated. The starting powder was synthesized via a novel wet chemical route. HA green compacts were prepared and sintered in atmospheric condition at various temperatures ranging from 900ºC-1300°C. The results revealed that the thermal stability of HA phase was not disrupted throughout the sintering regime employed. In general, the results showed that above 98% of theoretical density coupled with hardness of 7.21 GPa, fracture toughness of 1.17 MPam1/2 and Young’s modulus of above 110 GPa were obtained for HA sintered at temperature as low as 1050°C. Although the Young’s modulus varied linearly with increasing bulk density, the hardness and fracture toughness of the sintered material started to decline when the temperature was increased beyond 1000-1050ºC despite exhibiting high densities > 98% of theoretical value. The occurrence of this phenomenon is believed to be associated with a thermal-activated grain growth process.