Crystal structure of zirconia by Rietveld refinement

The crystal structures and phase transformation of zirconia ceramics have been investigated by means of X-ray powder diffraction and Rietveld powder diffraction profile fitting technique. A structural transition from monoclinic to tetragonal occurs when YOand CeOare doped into zirconia. The space group of the tetragonal structure is P4/nmc, Z=2. The lattice parameters are α=0.362 6（5） nm, c=0.522 6（3）nm for CeOdoped zirconia and α=0. 360 2（8）nm, c=0. 517 9（1）nm for YOdoped zirconia, respectively. In each unit cell, there are two kinds of equivalent positions, i. e. 2b and 4d, which are occupied by Zr, M(M=Y, Ce) cations and Oanions, respectively. The crystallographic correlation among the cubic, tetragonal and monoclinic structures of ZrOis discussed.