Mechanical properties of zirconia toughened alumina with 10–24 vol.% 1.5 mol% Y-TZP reinforcement

Structural ceramics such as ZTA require high bending strength, fracture toughness and wear resistance. In order to achieve optimum mechanical properties, processing and compositional parameters have to be adjusted. ZTA ceramics with an yttria content of 1.5 mol% and zirconia contents ranging from 10 to 24 vol.% were hot-pressed at 1475 °C at 50 MPa axial pressure. Stabilization of the reinforcement phase in ZTA with yttrium oxide was performed by coating of monoclinic zirconia nanopowders via the nitrate route and subsequent blending with sub-micron size alumina. Three different dwell times of 1–3 h were applied to test the sensitivity to heat treatment conditions. Mechanical and microstructural properties were investigated. Bending strength strongly depends on zirconia content and reaches a maximum of 1288 MPa at 24 vol.%. In a second step a variation of yttria stabilizer content from 1 to 2 mol% in 24 vol.% ZTA was tested to achieve further improvements of mechanical properties.