Multicomponent additive engineering for high-precision vat photopolymerization of Si3N4 ceramics

Vat photopolymerization technology has garnered significant attention in the field of ceramic additive manufacturing due to its high precision and efficient forming capabilities. However, a fundamental challenge remains in balancing the curing depth and printing accuracy during the fabrication of Si 3 N 4 ceramics. To address this issue, this study proposes a novel strategy for the synergistic modulation of slurry optical properties via the integration of a photoinitiator (PI, Irgacure 819), a UV absorber (UA, UV-531), and an oxygen scavenger (OI, BHT). Through a full-factorial experimental design, a multivariate nonlinear model was established. The results demonstrate that the photoinitiator (PI) enhances the polymerization efficiency by generating reactive radicals under UV exposure, while the UV absorber (UA) suppresses lateral over-curing by increasing the ultraviolet absorption coefficient, and the oxygen scavenger (OI) mitigates oxygen-induced inhibition of polymerization. The synergistic effects of these three additives maintain the curing depth within the range of 67.3–86.7 μm, while significantly improving the printing accuracy of submillimeter-scale microholes. The relative errors for square holes ranging from 200 to 500 μm were reduced to less than 2 %. The optimized slurry formulation ensures sufficient curing depth while markedly enhancing printing precision, enabling the rapid fabrication of high-resolution complex structures. This work provides a solid foundation for the advancement of vat photopolymerization of silicon nitride ceramics.