Phase stability and mechanical properties of TZP with a low mixed Nd2O3/Y2O3 stabiliser content

The phase assembly of 1.0–5.0 mol% Nd2O3-doped ZrO2 sintered at 1400 °C revealed that the tetragonal ZrO2 phase could not be completely stabilised. Co-stabilising of 0.5–2.5 mol% Nd2O3 with 0.5–1.0 mol% Y2O3, however, allowed the preparation of fully dense (Nd,Y)-TZP ceramics by pressureless sintering in air at 1450 °C. The mixed stabiliser monoclinic zirconia nanopowder starting material was synthesized from a suspension of neodymium nitrate, yttrium nitrate and monoclinic zirconia powder in an alcohol/water mixture. A HV30 hardness of 10 GPa combined with an excellent indentation toughness of 13 MPa m1/2 could be achieved for the (1.0Nd,1.0Y)- and (1.5Nd,1.0Y)-TZP ceramics. The influence of the mixed stabiliser content on the phase stability and mechanical properties are investigated and discussed.