Rheology and structure of ceramic stereolithography slurries: Role of powder nature, dispersant, and orthogonal strain

Abstract

We investigate the rheological properties of ceramic slurries designed for laser stereolithography manufacturing in relation to their formulation, including the powder morphology, their volume fraction, and the concentration of dispersing agent. By combining dynamic strain sweep and Small-Angle X-ray Scattering (SAXS) experiments, we first illustrate that slurry viscosity follows an exponential trend with increasing particles content, with steeper increase observed for more aggregated particles. We then show that increasing the dispersant concentration up to an optimal value decreases slurry viscosity, as SAXS measurements reveal a reduction and homogenization in agglomerate size. Finally, we evidence that applying vertical oscillatory deformation during steady shear flow induces fluidization of the slurry. The shear viscosity exhibits a time–strain rate equivalence, enabling the generalization of this effect across a wide range of formulations. This methodology holds potential for industrial applications, where introducing vibration perpendicular to the scraping blade motion could improve the surface quality of the spread slurry prior to polymerization.