Three‐dimensional printing of zirconia scaffolds for load bearing applications: Study of the optimal fabrication conditions
Anuraag Gaddam, Daniela Brazete, Ana S. Neto, Bo Nan, J.M.F. Ferreira
Abstract
Abstract Yttria‐stabilized zirconia (YSZ) scaffolds with a planned macroporosity fraction of about 70% were fabricated by Robocasting from inks with high solid loadings. The effects of solids loading and the concentrations of processing additives on the flow behavior of the starting suspensions and the viscoelastic properties of the resulting inks were investigated aiming at optimizing the printing process. The shear thinning flow behavior of the starting suspensions containing 45‒48 vol% solids and dispersant concentrations varying within 0.2‒0.8 wt% could be well described by the four‐parameter Cross model. The flow behavior of the suspensions could be correlated with the interaction forces, and the ad‐layer thickness formed around the YSZ particles. Further adding suitable amounts of a binder and a coagulating agent enabled optimizing the viscoelastic properties of inks for 3D printing. Good shape retention was observed for inks with elastic modulus, G′ ≥ 10 MPa. The green scaffolds were dried, sintered at 1350°C, and then used for the assessment of porosity and mechanical properties under compression tests. The porous structures exhibit average compressive strength ( σ ) of ~70 MPa. Weibull statistics applied to σ data revealed good reliability of the process, which can be used to fabricate YSZ scaffolds for orthopedic applications.