Effect of Temperature and Time on the Sintering, Phase Stability, Microstructure and Microhardness of Commercially Available Hydroxyapatite
A commercially available hydroxyapatite (HA) was sintered for a number of sintering temperatures and times between 1150°C to 1350°C and 0 to 12 hours respectively. Full density was reached after sintering for 1.5 hours at 1250°C and a maximum microhardness of 4.9GPa was achieved after 6 hours at 1300°C. Significant grain growth occurred but did not seem to influence the microhardness observed. Significant decomposition was observed after sintering at 1350°C for 1.5 which lead to major decreases in microhardness. An activation energy for grain growth of 286 kJ.mol-1 was calculated which is substantially higher than that previously noted for HA.
Panjian Li, Kai Zhang and Clifford W. Colwell, Jr.
F.P. Cox et al., "Effect of Temperature and Time on the Sintering, Phase Stability, Microstructure and Microhardness of Commercially Available Hydroxyapatite ", Key Engineering Materials, Vols. 284-286, pp. 345-348, 2005