Replacing metal by ceramic implants is becoming increasingly viable. The most realistic replacement is 3Y-TZP due to its mechanical and aesthetic properties (especially for dental implants). Still, low-temperature degradation (LTD) remains one possible disadvantage, which is enhanced in the wet oral environment. To prevent the material’s failure due to LTD, ceria-stabilized zirconia could be a suitable hydrothermally stable alternative.
Different techniques can be used to produce ceramic implants, but additive manufacturing offers better customization with less waste material. Direct ink writing (DIW) is an additive manufacturing technique based on micro-extrusion of highly concentrated slurries through a narrow conical nozzle deposited in a continuously spatially controlled filament and a layer-wise fashion. To ensure easy flow through a nozzle and sufficient yield stress to support layer stacking, DIW inks need to have adequate shear-thinning flow and viscoelastic properties. Printing followed by proper drying and sintering routes is supposed to render fully dense monolithic disks.
In this work, a water-based hydrogel (Pluronic F-127) was used as a carrier for CeO2-stabilized zirconia-ceramic powders because it allows fine adjustment of the suspension rheology while obtaining stable inks. Starting powder, dispersant and hydrogel content affect the ink stability and viscoelastic behavior. Based on rheological analysis, maximum solid loading in extrusion inks has been studied. Moreover, printing parameters and repeatability of the printing process were also investigated.
SEM and µCT characterization of printing defects and density were examined on sintered samples.