Optimisation of ink preparation for direct ink writing of defect-free, high-density Ce-TZP ceramics

Abstract

Direct ink writing (DIW) has emerged as a promising technique for fabricating dense ceramic components, focusing on yttria-stabilised tetragonal zirconia polycrystal (Y-TZP). However, the application of DIW to ceria-stabilised zirconia (Ce-TZP) remains relatively unexplored. A critical factor in achieving dense, defect-free ceramic prints is the formulation of inks that balance optimal rheological properties with high solid loadings. This study investigates the influence of dispersion and mixing protocols on ink rheology and printing parameters, ultimately correlating these factors with the mechanical properties of the sintered components. Pre-milling the ceramic powder with a dispersant before hydrogel addition allowed producing highly homogeneous inks with minimal agglomeration, leading to consistent printing and high-density parts. The maximum achievable solid loading for these Ce-TZP inks, utilising 0.5 wt% Dolapix dispersant within a 25 wt% Pluronic F-127 solution, was 40 vol%. Notably, the mechanical properties of these DIW-produced components were comparable to those of conventionally processed ceramics.