Microstructures and mechanical properties of 8Y-FSZ ceramics with BaTiO3 additive

The microstructure and mechanical properties of 8 mol% Y2O3 fully stabilized zirconia (8Y-FSZ) with BaTiO3 additive were investigated. The introduction of BaTiO3 additive would significantly increase the density and the grain size of 8Y-FSZ ceramics. XRD, Raman spectroscopy, and dielectric measurement were performed. A rhombohedral Ba(Ti1−xZrx)O3 ferroelectric phase resulted in the composite with 5 mol% additive, while for those with higher additive content, the secondary phase changes to cubic Ba(Ti1−xZrx)O3. The fracture toughness of the xBaTiO3/(1−x)8Y-FSZ composites reached a maximum and then decreased with increasing the amount of additive. The highest value reached 6.1 MPa m1/2 for 0.05BaTiO3/0.95(8Y-FSZ) sintered at 1475 °C for 3 h, where the piezoelectric/ferroelectric secondary phase toughening played an important role. Moreover, the fracture toughness of the composites increased firstly and then decreased with increasing sintering temperature.