Effect of solid volume fraction of slurries on properties of zirconia-toughened alumina composite ceramics by gelcasting

The effect of solid volume fraction in slurries on physico-mechanical properties was investigated for zirconia-toughened alumina (ZTA) green and sintering bodies prepared by gelcasting process. The mass ratio of Al₂O₃ and ZrO₂ was 80:20 in experiment. The pore structures of green bodies were analyzed with the mercury intrusion method. The results indicate that pore distribution of green bodies prepared by slurries with high solid volume fraction appears double peaks. SEM photographs and XRD patterns show that sintered samples made by slurries with high solid volume fraction have a higher densification structure, homogeneous distribution of ZrO₂ particle and higher content of t-ZrO₂, phase. The bending strength and fracture toughness of the ZTA ceramics prepared by the slurry with 55% solid volume fraction and sintered at 1600°C for 2 h can be reached to 631.5 MPa and 7.64 MPa · m^1/2, respectively.