Fabrication and characterization of ZrO2(3Y)/Al2O3 micro-ceramic gears with high performance by vat photopolymerization 3D printing

To date, overcoming the trade-off between high solid loading and print accuracy and strength, achieving high -performance and fine ZrO2 micro-ceramic components through vat photopolymerization 3D printing remains challenging. In this study, the effects of dispersant, particle size and solid content on the dispersion, rheological behavior and stability of ZrO2 ceramic slurry were systematically studied, and complex, fine and high -performance ZrO2 micro-ceramic gears were successfully prepared. Then, the microstructure, mechanical properties, tribological properties and surface quality were evaluated. The results show that the rheological behavior of the slurry is the best when the optimal dispersant content is 3.5 wt%. With the increase of solid content, the sintering shrinkage of ZrO2(3Y)/Al2O3 ceramics decreased, while the relative density, compressive strength, flexural strength, fracture toughness and hardness increased. The prepared micro-ceramic gears not only have fine structure, but also have dense microstructure and good mechanical properties. The relative density, compressive strength, flexural strength, fracture toughness and hardness strength of ZrO2(3Y)/Al2O3 ceramics can reach 98.53 %, 1900 MPa, 648 MPa, 6.4 MPa x m1/2 and 13.40 GPa, respectively. In particular, this study couples the printing accuracy and strength with the solid load. By adjusting the relationship between the fixed load and the shrinkage rate, the printing of samples with different sizes is realized, which breaks through the accuracy limit of the printing equipment and provides a new idea for the preparation of micro-ceramic gears.