Photosensitive Si3N4 slurry with combined benefits of low viscosity and large cured depth for digital light processing 3D printing

Abstract

Digital light processing 3D printing can be applied to fabricate complex silicon nitride (Si3N4) components. However, because of the surface hydroxyl groups and large refractive index, it is still a foremost challenge to realize a stable photosensitive Si3N4 slurry with combined benefits of low viscosity and large curing depth. In this study, we propose a new formulation strategy to prepare Si3N4 slurry. Starting from the optimization of monomer ratio, we have systematically optimized powder particle size, dispersant and photoinitiator on the rheological properties and curing properties of Si3N4 slurry. Specifically, we have fabricated a stable photosensitive Si3N4 slurry (48 vol%) with a viscosity of 2.09 Pa s (30 s−1), a critical curing energy of 126.09 mJ/cm2 and a maximum curing depth of 80 µm. Finally, based on this optimized slurry, we have successfully obtained complex Si3N4 green body with no defect, which demonstrates great potential to fabricate arbitrary complex ceramic components for various applications.