Characterization of mechanical properties and bioactivity of hydroxyapatite/β-tricalcium phosphate composites

Abstract

Bioactive ceramics attracts much attention as materials for bone implants, because of their high biocompatibility. For example, hydroxyapatite (HA) has bone-bonding ability through a bone-like apatite layer in body environment and β-tricalcium phosphate (β-TCP) has a high bioresorbability in body environment. In this study, HA/β-TCP composites with different β-TCP content (0, 10, 20, and 30 wt.%) were prepared by wet mixing of HA and β-TCP powders, compaction of the powder mixture and sintering. Bending strength of HA/β-TCP composites was measured before and after soaking in simulated body fluid (SBF). The bioactivity of HA/β-TCP composites was also evaluated by soaking in SBF. To improve mechanical properties of HA/β-TCP composites, effects of additive of SiO2 and MgO were also investigated. It was found that the several mechanical properties and ability of apatite formation decreased with β-TCP content. It was also found that the change in bending strength after soaking depended on its surface reaction in SBF and porosity. Addition of SiO2 did not improve mechanical properties and bioactivity. On the other hand, additive of MgO improved several mechanical properties, but lowered the bioactivity in SBF.