Microstructure control of TCP/TCP-(t-ZrO2)/t-ZrO2 composites for artificial cortical bone

In this study, bone like continuously porous TCP/TCP-(t-ZrO2)/t-ZrO2 composites with a central channel were fabricated using a multi-pass extrusion process and their mechanical properties and microstructure at different sintering temperatures were investigated. Hydroxyapatite (HAp) powder was used as the raw powder which undergoes a phase transformation into the α-tricalcium phosphate phase (α-TCP) at a sintering temperature of 1500 °C. The external diameter and inside cylindrical hollow core were approximately 10.3 mm and 4.8 mm, respectively. The frame region contained numerous microchannels that extended from one side of the fabricated body to the other. The channeled frame region had a multi-layer microstructure with a TCP/TCP-(t-ZrO2)/t-ZrO2 layer configuration. The inner layer consisted of TCP, which make the wall of the microchannel. The material properties were characterized and microstructural analysis was carried out. The maximum pore size, compressive strength, and relative density of the fabricated system were approximately 86 μm, 53 MPa, and 77% when sintered at 1500 °C. The composites exhibited excellent biocompatibility and cell proliferation behavior resulted in the MTT assay and cell adhesion test using osteoblast-like MG-63 cells.