Vat photopolymerization of silica-based ceramic cores using high solid loading slurry with performance optimization

Vat photopolymerization (VPP) 3D printing is an optimized technology for complex-shaped ceramic cores, in which the solid loading of ceramic slurries greatly influences the microstructure and property of the final ceramic parts. However, the high solid loading of slurries is highly limited by the high viscosity. In this study, silica-based ceramic core slurries with solid loading up to 68vol.% were achieved by the composition design to optimize the performance, considering the curing, rheological, and double bond conversion rate. The slurries demonstrate superior curing and rheological performance with mass ratio of monomers being 3:2 and mass fraction of BYK111 being 4wt.%. Afterwards, the impact of solid loading on the morphology and mechanical properties was investigated. As the solid loading increases, the microstructure becomes gradually dense, leading to an improved flexural strength of 19.5 MPa. Additionally, the sintering shrinkage becomes more uniform, satisfying the casting requirements effectively. This work serves as a guide for the preparation of ceramic slurries with a high solid loading.