Fabrication and Mechanical Properties of CeO₂ Stabilized Tetragonal Zirconia Based Nanocomposites Incorporating Al₂O₃ Dispersions

Abstract

To compensate the definite disadvantages of ceria stabilized tetragonal zirconia polycrystal (Ce-TZP) as compared to Y-TZP ceramics, such as lower strength and lower hardness, we applied the idea of the nanocomposite to Ce-TZP/Al₂O₃ composite system. Zirconia matrix in these composites consisted of primarily the tetragonal phase and a small amount of the monoclinic phase. These composites partly possessed an intragranular nanostructure, in which fine alumina particles were trapped within the zirconia grains. At an optimum component for the 10Ce-TZP/30vol% Al₂O₃ composite sintered at 1500°C, strength of 730 MPa and very high toughness of 10.2 Mpa.m_1/2 (SEPB) were achieved. This toughness value was in excess of that (8.1 MPa⋅m_1/2) of WC/Co cermet. Therefore, it is suggested that this composite system would be expected as candidate for an attractive TZP ceramics, which have advantages of both high strength in Y-TZP and high toughness in Ce-TZP along with high resistance to low-temperature degradation.