Yb2O3 and Y2O3 co-doped zirconia ceramics

A suspension stabilizer-coating technique was employed to prepare x mol% Yb2O3 (x = 1.0, 2.0, 3.0 and 4.0) and 1.0 mol% Y2O3 co-doped ZrO2 powder. A systematic study was conducted on the sintering behaviour, phase assemblage, microstructural development and mechanical properties of Yb2O3 and Y2O3 co-doped zirconia ceramics. Fully dense ZrO2 ceramics were obtained by means of pressureless sintering in air for 1 h at 1450 °C. The phase composition of the ceramics could be controlled by tuning the Yb2O3 content and the sintering parameters. Polycrystalline tetragonal ZrO2 (TZP) and fully stabilised cubic ZrO2 (FSZ) were achieved in the 1.0 mol% Y2O3 stabilised ceramic, co-doped with 1.0 mol% Yb2O3 and 4.0 mol% Yb2O3, respectively. The amount of stabilizer needed to form cubic ZrO2 phase in the Yb2O3 and Y2O3 co-doped ZrO2 ceramics was lower than that of single phase Y2O3-doped materials. The indentation fracture toughness could be tailored up to 8.5 MPa m1/2 in combination with a hardness of 12 GPa by sintering a 1.0 mol% Yb2O3 and 1.0 mol% Y2O3 ceramic at 1450 °C for 1 h.