Mechanical properties of Nd2O3/Y2O3-coated zirconia ceramics

1.5–2 mol% Nd2O3–1.5 mol% Y2O3-coated zirconia nanopowders were prepared from a suspension of neodymium nitrate, yttrium nitrate and monoclinic zirconia powder in an alcohol/water mixture. The influence of the stabilizer content and sintering time on the microstructure and mechanical properties of the densified ceramics was investigated. Fully dense (Nd, Y)-TZP ceramics with an excellent combination of hardness and fracture toughness could be obtained by pressureless sintering in air at 1450 °C. A typical HV30 hardness of 10 GPa was obtained and the fracture toughness could be tailored up to 11.5 MPa m1/2 for 2 mol% Nd2O3–1.5 mol% Y2O3-coated ZrO2 powder sintered for 3 h. The dependence of the fracture toughness on the sintering time is explained in terms of grain growth.