Mechanical Properties of 3Y-TZP Woodpile Scaffold Made by Extrusion 3D Printing

Zirconia woodpile scaffolds (3Y-TZP/PL, n = 20), designed with null inter-filament spacing, were manufactured using the Direct Ink Writing (DIW), an extrusion 3D printing technique. A ceramic ink containing 40%v/v 3Y-TZP powder, 59%v/v PEG (Polyethylene glycol)/Laponite ink, and 1%v/v DBP (Dibutylphthalate) was used. For 3D printing, we used Ø 0.63 mm nozzles, a printing speed of 10 mm/s, a cross-layer deposition strategy, and no air gaps between filaments. The scaffolds were sintered at 1550 °C for 2 h. The mechanical characterization involved measurements of X-ray diffraction, scanning electron microscopy, Vickers microhardness, Vickers nanohardness, and modulus of elasticity and compressive strength. The sintered samples showed predominantly the ZrO2-tetragonal phase and a microstructure characterized by a bimodal distribution of grain sizes. The samples had a relative density of 90.1 ±1.5%, a Vickers microhardness of 1172 ±45 HV, a Vickers nanohardness of 1608 ±78 HV, a modulus of elasticity of 203 ±16 GPa, and a compressive strength of 192 ±54 MPa. The results showed that DIW processing followed by proper sintering is a promising method for making zirconia scaffolds for biomedical applications.