Alumina toughened zirconia made by room temperature extrusion of ceramic pastes

A novel preparation route for ATZ (alumina toughened zirconia) ceramics is presented, using a commercial ATZ powder (a mixture of 20 wt.% alumina and 80 wt.% zirconia containing 3 mol.% yttria) as a solid filler and an ATZ so l or gel (of the same composition) as a liquid binder for paste extrusion a t room temperature. The pastes have a total oxide content of approx. 70 wt. % and during heat treatment the binder composition accommodates to the comp osition of the filler powder. Extruded samples are characterized before and after heat treatment by determining their shrinkage, bulk density, apparen t density and apparent porosity. The optimal firing temperature is determin ed to be about 1550 degrees C. quantitative X-ray phase analysis is used to establish the phase composition (ratio of monoclinic to tetragonal zirconi a) and to calculate a (spatially averaged) mean value for the true density of the prepared nanocomposite after firing, which is 5.45 g cm(-3). For opt imally sintered specimens the bulk density is approx. 5.06 g cm(-3), i.e. 9 2.8% of the theoretical value. The total porosity after sintering is approx . 6.8% (open 4.7%, closed 2.1%).