Ceramic polymer composite slurries were prepared using nano- and micro-sized Al2O3 in order to analyze rheological properties, sedimentation, and curing behavior. Slurries with different Al2O3 particle sizes were prepared with varying concentrations of photoinitiator, and subjected to different exposure times to prepare a printing object. All slurries exhibit shear-thinning behavior, and the viscosity increases with decreasing Al2O3 particle size. The 100 nm Al2O3 slurry is confirmed to be more sol-like, while the 500 nm and 2 μm Al2O3 slurries have a gel-like structure. As the Al2O3 particle size increases, a thick sedimentation layer forms due to rapid settling, but as the distance between particles increases, the UV light scattering reduces, and the curing rate increases. The exposure time range viable for printing, and the dimension conformity of the printed specimen with the design file, is improved by increasing the Al2O3 particle size. In the case of 500 nm and 2 μm Al2O3 slurries, the maximum heat flow, curing enthalpy, and conversion rate are high with respect to photoinitiator concentration, in the order of 1.0 > 0.1 > 3.0 wt.%. When the photoinitiator concentration exceeds 1 wt.%, it appears to affect the reactivity of the slurry.
Keywords: ceramic 3D printing; particle size; photocuring; photoinitiator concentration; slurry properties.