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.