Influence of Al₂O₃ addition on the microstructure and mechanical properties of pressureless sintered Ce-TZP

Mixtures of 12 mol% CeO₂-stabilised ZrO₂ with 5 to 20 wt % Al₂O₃ were prepared and densified through pressureless sintering in air at 1450 °C for 1 to 4 h. The influence of the Al₂O₃ content and sintering time on the phase constitution, microstructure and mechanical properties of the as-sintered composites were investigated. Fully dense Ce-TZP/Al₂O₃ ceramics with a good combination of hardness and fracture toughness can be obtained by pressureless sintering in air for only 1 h. The addition of Al₂O₃ to Ce-TZP improves the mechanical properties and suppresses ZrO₂ grain growth. The average ZrO₂ grain size increases with increasing sintering time and decreasing Al₂O₃ content. This leads to an increase in toughness. An excellent fracture toughness of 14.3 MPam½ in combination with a Vickers hardness of 9.14 GPa was obtained for 12 mol CeO₂-TZP with 5 wt % Al₂O₃, sintered for 4 h.status: publishe