Peculiarities of Yttria- and Ceria-Stabilized Zirconia Ceramics Fabricated via Electroconsolidation

Zirconia-based ceramics find wide application in engineering due to their very high hardness, resistance to elevated temperatures, and high fracture toughness. Among stabilizers of the advantageous tetragonal zirconia phase, yttria allows for better grain size refinement than ceria does; thus, Y₂O₃ is the most widely used. In the present study, comparative analysis was performed for yttria-stabilized zirconia (YSZ) and ceria-stabilized zirconia (CSZ) in terms of sinterability, densification, and mechanical properties, including hardness and resistance to plastic deformation. The results proved that CSZ sintered in similar conditions as YSZ exhibits similar properties, including an elastic modulus of 200-220 GPa and <i>H/E</i> of 0.070-0.076. In particular, the hardness of the ZrO₂-5 wt% CeO₂ ceramic appeared to be 14.6 ± 0.5 GPa, close to that of ZrO₂-3 wt% Y₂O₃, which was 14.20 ± 0.74 GPa. However, SiC addition to ZrO₂-5 wt% CeO₂ composites increased hardness substantially up to 16.8 ± 0.8 GPa. Moreover, the fracture toughness of CSZ was 2.5 times higher than that of YSZ sintered under identical conditions. Thus, CeO₂ can be a good, cheaper alternative to the traditionally used Y₂O₃ stabilizer for submicron-grained tetragonal zirconia ceramics.