Hydrothermal synthesis of porous hydroxyapatite ceramics composed of rod-shaped particles and evaluation of their fracture behavior

We previously reported that porous hydroxyapatite (HA) ceramics composed of rod-shaped particles exhibited high functional ability to be integrated in natural bone quickly compared to sintered HA ceramics. In addition to improved biological properties, rod-shaped particles might also provide unique mechanical properties to the HA porous ceramics. In this study, porous HA ceramics composed of rod-shaped HA particles with different aspect ratios were synthesized by a hydrothermal process, and their fracture behavior was examined by a flexural test. As the reaction temperature in the hydrothermal process decreased, the aspect ratio of the resultant particles increased and was successfully controlled from 13 to 37. Porous HA ceramics composed of rod-shaped particles with large aspect ratios exhibited non-elastic deformation in the flexural test. As the aspect ratio of the particles increased, the flexural strength and strain at fracture increased. Furthermore, the flexural strength and strain at fracture of the porous HA ceramics composed of rod-shaped particles with large aspect ratios was higher than that of sintered porous HA ceramics with a similar porosity.