Yttria-Calcia-Co-Stabilized Tetragonal Zirconia Polycrystals Made by Powder Mixing

In this study 1.5Y-2.2Ca-TZP materials were obtained by hot pressing of a mixed and milled blend of 3Y-TZP and 4.4Ca-TZP powders. The materials were sintered at temperatures between 1250–1400 °C and characterized with respect to mechanical properties, microstructure phase composition and stability against low temperature degradation. In the tested range, the bending strength of the TZP decreases with increasing sintering temperature from 1300 MPa to 1050 MPa while the toughness shows a rising trend from 5 MPa√m to 8 MPa√m. The microstructure is bimodal with grain sizes increasing from 140 nm to 300 nm with rising sintering temperature. LTD tests revealed high ageing resistance for TZP sintered at 1300 °C. The Y-Ca-co-stabilized TZP equilibrates the properties of Ca-TZP and Y-TZP.