Influence of temperature field on the rheological properties and photopolymerization process of Mg2TiO4 microwave ceramic slurry during vat photopolymerization process

Temperature-field-assisted vat photopolymerization has been applied to prepare Mg2TiO4 ceramics with few defects and remarkably reduced dielectric loss. These excellent properties could be attributed to the significantly reduced viscosity and increased curing depth of the prepared ceramic slurry with a high solid loading when the photopolymerization temperature reaches 65 °С. Increasing the temperature helped to increase the kinetic energy of the resin molecules and reduce the viscosity of the ceramic slurry. This ensured a smooth spreading of the slurry and suppressed the formation of intra-layer defects during the printing process. Additionally, increasing the curing temperature enhanced the activation energy of the free radicals and accelerated the transfer of molecular chains, thereby increasing the polymerization rate and curing depth of the slurry. This reduced the interlayer pores of the Mg2TiO4 green bodies. Thus, Mg2TiO4 ceramic slurry with a high solid loading could be successfully printed by applying a temperature field. Significantly fewer defects were found in Mg2TiO4 ceramics printed with 57.5 vol% solid loading than those in the samples printed with 50 vol% solid loading. The quality factor of Mg2TiO4 ceramics sintered at 1550 °С for 4 h using ceramic slurries with 57.5 vol% solid loading could reach 150,000 GHz when printed at a curing temperature of 65 °С, this value is equivalent to that of dry-pressed ceramics.