Optimizing Zirconia Slurry via Particle Gradation for Enhanced Reticulated Porous Ceramics

The preparation of zirconia porous ceramics is typically accomplished using the organic foam impregnation method. In this process, the rheological properties of the slurry significantly influence the physical characteristics of the final porous ceramics. High viscosity results in a decreased porosity of zirconia porous ceramic, whereas low viscosity leads to its low mechanical property. To address this issue, particle gradation in binary, ternary, and quaternary systems was designed to enhance the rheological properties of zirconia slurry, thereby strengthening the porous ceramics. The results indicated that increasing the gradation number and enlarging the critical particle size broadened the particle distribution and enhanced the packing density of zirconia slurries, improving their rheological properties. Notably, the binary system exhibited the highest slurry viscosity. However, incorporation of critical‐sized particles (1 µm) into ternary systems effectively reduced viscosity. This finding was further validated using the improved Andreasen model. Following heat treatment at the optimal sintering temperature of 1773 K, this formulation resulted in zirconia porous ceramics with a porosity of 83.69%, with a bulk density of 0.90 g/cm 3 , a strut density of 3.36 g/cm 3 , and the highest residual strength retention rate of 86.32%.