Effect of silica particle size on the viscosity, curing behavior, and sintering performance of silica/alumina ceramic suspensions for digital light processing-based vat photopolymerization

This study systematically examined the effect of silica particle size on the viscosity, curing behavior, and sintering properties of silica/alumina ceramic suspensions. The suspension with 200 nm silica has a significantly higher viscosity than those with 500 nm and 1 μm silica. During digital light processing-based vat photopolymerization (VPP), the suspension with 200 nm silica exhibited the lowest cure depth and cure width. The sample's shrinkage and densification after sintering at different temperatures were also analyzed. At the same temperature, the silica particle size only weakly affected the shrinkage and densification. However, X-ray diffraction analysis of sintered samples revealed that a smaller particle size significantly facilitated the formation of the mullite phase. Finally, high-quality mullite ceramics with clear outlines were successfully prepared. This research provides an experimental foundation for the in-situ synthesis of complex mullite ceramic structures using VPP.