Effect of zirconia content and particle size on the properties of 3D-printed alumina-based ceramic cores

Alumina-based ceramic cores are used to manufacture the internal structures of hollow alloy blades, requiring both high precision and moderate properties. In this work, zirconia is regarded as a promoter to improve the mechanical properties of sintered ceramic. The effect of zirconia content and particle size on the microstructure and mechanical properties of ceramics was evaluated. The results indicate that the flexural strength of sintered ceramics reached the maximum of 14.5 ± 0.5 MPa when 20 wt% micron-sized (10 μm) zirconia (agglomerate size, consistent with the alumina particle size) was added, and 26.5±2.5 MPa when 15 wt% 0.3 μm zirconia was added. Zirconia with submicron-sized (0.3 μm) particles effectively filled the pores between alumina particles, thus leading to the maximum flexural strength with a relatively low content. The corresponding sintered ceramics had a bulk density of 2.0 g/cm³ and open porosity of 59.6%.