Vat photopolymerization 3D printing of alumina ceramics with low sintering temperature

Alumina (Al₂O₃) ceramic is widely used in various industrial applications due to its excellent mechanical properties and environmental stability. 3D printing technology endows ceramic components with more design flexibility and manufacturing efficiency. However, the high sintering temperature of Al₂O₃ (typically above 1600 °C) has hindered its integration with other functional ceramics or metals, thereby restricting its broader application. In this work, we developed a series of photosensitive Al₂O₃ slurries with different sintering aids suitable for vat photopolymerization 3D printing. Optimal sintering temperatures of 1450 °C and 1250 °C for 3D-printed Al₂O₃ ceramics were achieved by adding 3.5 wt% TiO₂ and 3.5 wt% CuO–Mg(OH)₂–TiO₂ as sintering aids, respectively. We investigated the viscosities and curing behaviors of these Al₂O₃ slurries, as well as the phase compositions, microstructures, and mechanical properties of Al₂O₃ ceramics after sintering. Various cellular and lattice structures were fabricated by 3D printing to demonstrate their good printability and excellent mechanical properties.