The structure transformations in nanocrystalline zirconia

The special features of the structure and phase composition of nanocrystalline zirconia-based powders are studied. The investigations show that an increase in the monoclinic phase abundance is associated with a reduction in the critical size of tetragonal crystallites due to an accumulation of lattice microdistortions. This is attributed to the fact that the resultant lattice microdistortion level is inadequate to destabilize the nanocrystalline tetragonal phase. Relaxation of microdistortions on annealing causes the critical size of tetragonal crystallites to increase and the monoclinic phase is converted into the tetragonal one