Sintering kinetics of cerium-stabilised tetragonal zirconia

Zirconia ceramics stabilised by CeO2 (Ce-ZrO2) exhibit low strength owing to their coarse grain sizes, which are typically larger than 1–2 μm. A promising approach to enhance the mechanical properties of Ce-ZrO2 is refining of the grain size. This study focuses on achieving fully dense Ce-ZrO2 ceramics with sub-micron grain sizes by identifying a sintering kinetic window that facilitates active sintering while suppressing grain growth. Both non-isothermal and isothermal sintering techniques were systematically employed to investigate the sintering and grain growth behaviour of the Ce-ZrO2 ceramics. The activation energies for sintering and grain growth were also determined. The existence of a sintering kinetic window for the Ce-ZrO2 ceramics was confirmed by a comparative analysis of the calculated activation energies. Accordingly, we successfully prepared fully dense sub-micron Ce-ZrO2 ceramics (with relative density >98%) by sintering within this kinetic window, leading to an average grain size of 0.55 μm. This is a significant step towards tailoring the microstructure of Ce-ZrO2 ceramics to improve their mechanical performance.