Influence of precursor powder characteristics on the microstructure and microwave dielectric properties of vat-photopolymerized Zn2SiO4–TiO2 ceramics

The additive manufacturing of complex Zn 2 SiO 4 –TiO 2 (ZST) microwave dielectric ceramics via vat photopolymerization (VPP) presents challenges in balancing densification with phase purity. This study systematically investigates how the initial SiO 2 precursor particle size (30 nm, 300 nm, and 5 μm) governs the entire process–property relationship. While the use of nano-sized SiO 2 particles promoted sintering activity and improved densification, it also led to the emergence of a secondary phase with high dielectric loss, which adversely affected the quality factor ( Q  ×  f ). Conversely, larger (micron-sized) particles suppress this impurity, ensuring high phase purity at the cost of slightly lower density. By leveraging this understanding, the ZST ceramic derived from 5 μm SiO 2 (ZST3) achieved a favorable balance of properties, exhibiting a high quality factor ( Q  ×  f ), a suitable dielectric constant ( ε r ), and excellent thermal stability with a near-zero τ f value. This study demonstrates that controlling the precursor particle size is an effective method for tailoring the microstructure and phase composition, thereby enhancing the performance of additively manufactured microwave dielectrics.