Influence of Al_2O_3 Addition on the Microstructure and Mechanical Properties of Pressureless Sintered Ce-TZP

摘要

Mixtures of 12 mol% CeO_2-stabilised ZrO_2 with 5 to 20 wt % Al_2O_3 were prepared and densified through pressureless sintering in air at 1450°C for 1 to 4 h. The influence of the Al_2O_3 content and sintering time on the phase constitution, microstructure and mechanical properties of the as-sintered composites were investigated. Fully dense Ce-TZP/Al_2O_3 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 Al_2O_3 to Ce-TZP improves the mechanical properties and suppresses ZrO_2 grain growth. The average ZrO_2 grain size increases with increasing sintering time and decreasing Al_2O_3 content. This leads to an increase in toughness. An excellent fracture toughness of 14.3 MPam~(1/2) in combination with a Vickers hardness of 9.14 GPa was obtained for 12 mol % CeO_2-TZP with 5 wt % Al_2O_3, sintered for 4 h.