The new rheological model for zirconia suspensions with long-term kinetic stability

Abstract

For successful 3D printing based on stereolithography technologies, one of the most important factors influencing the success of printing is the dynamic viscosity of the prepared suspension. For the purposes of viscosity prediction at different volume fillings, two ZrO2 powders with different yttrium content (CY3Z-RS and CY8Z-RS) with volume filling 0 – 40 % in two different dispersing mediums at two temperatures were investigated in this paper. The dependence of relative viscosity on volumetric filling was fitted by existing models and a new semi-empirical model based on experimental data was proposed and successfully plotted. Fitted data for all zirconia photosensitive suspensions showed a high correlation to the proposed model (R2 from 97.02 % to 99.61 %). The model in addition to the possibilities of mathematical generalization of his prescription, introduces a fitting parameter C, which is thought to be thermodynamically influenceable and predictable. Furthermore, another key characteristic that is often neglected in rheological characterization, the stability of prepared ceramic suspensions, was verified either by rheological measurements but also by employing prospective technology based on analytical centrifuge. It was confirmed that all prepared suspensions were highly stable, and all instability indexes reached values less than 0.05.