Pulse electric current sintering of hydroxyapatite/-tricalcium phosphate composites

Hydroxyapatite (HA)/-tricalcium phosphate (-TCP) composites attract attentions as bone implant materials. As one of the fabrication method of HA/-TCP is mixing of HA and -TCP powder in advance of sintering. This method enables to control the ratio of content of -TCP easier. However, it is difficult to obtain dense composites. In this study, we focused on pulse electric current sintering (PECS) to obtain dense HA/-TCP composites. The sinterability is evaluated with relative density and grain size measurements. Composition of sintered body was also characterized by X-ray diffraction. In comparison with pressureless sintering, PECS increased relative density of the composites without grain growth. In HA/-TCP sintered by PECS, the phase transformation from -TCP to -TCP was promoted. This is due to higher thermal energy by spark discharge during PECS. On the other hand, sintering additives (MgO) inhibited phase transformation. It was suggested that sinterability of HA/-TCP composites was improved by PECS.