Effect of AlN content on microstructure and properties of SiAlON ceramics prepared via vat photopolymerization

To date, the application of additive manufacturing techniques in fabricating SiAlON ceramics with intricate geometries has been limited. This investigation demonstrates the synthesis of SiAlON ceramics by integrating silicon nitride (Si₃N₄) powders with variable proportions of aluminum nitride (AlN) utilizing the vat photopolymerization (VPP) approach. The effects of AlN content on the properties of SiAlON ceramic slurries, green bodies, and sintered parts were systematically investigated. Notably, the slurry's viscosity decreases progressively with an increase in AlN, aligning with VPP printing prerequisites. Additionally, the curing depth of the slurry enhanced proportionally with AlN augmentation, elevating from 21 μm to 44 μm at an energy exposure of 800 mJ/cm², with the pivotal addition being 15 vol% AlN, where optimal properties were achieved. The zeniths of flexural strength, bulk density, relative density, and thermal conductivity were recorded at 385.66 ± 22.63 MPa, 3.34 ± 0.09 g/cm³, 96.22 ± 2.55 %, and 37.4 ± 0.31 W m⁻¹ K⁻¹, respectively. The fabrication of SiAlON ceramics with complex configurations was successfully realized, heralding a novel methodology for future SiAlON ceramic production.