Densification and Grain Growth of Nanocrystalline Zirconia-Based Ceramics

Abstract

The sintering behavior of ZrO 2 -14 wt. % Al 2 O 3 nanocomposites between 1000 and 1200 °C was investigated and compared with the results obtained for pure nanocrystalline ZrO 2 . The highest density found in pure nanocrystalline ZrO 2 was 92 % with a grain size of 72 nm at 1000°C. Nanocrystalline ZrO 2 -Al 2 O 3 composites reached densities of 97 % with a corresponding grain size of 35 nm at 1200°C. The results are discussed in terms of the level of agglomeration of the initial powders compacts and the pinning of grain boundaries by dispersed nanoparticles. Pure nanocrystalline ZrO 2 is monoclinic at all temperatures; the nanocrystalline composite exhibits a transformation from the monoclinic to the tetragonal phase with a maximum volume fraction of approx. 80 % at 1050 °C.