Crystal structure of zirconia by Rietveld refinement

crystal structures and phase transformation of zirconia ceramics have been investigated by means of X-ray powder diffraction and Rietveld powder diffr action profile fitting technique. A structural transition from monoclinic t o tetragonal occurs when Y2O3 and CeO2 are doped into zirconia. The space g roup of the tetragonal structure is P4(2)/nmc, Z=2. The lattice parameters are a =0.362 6(5)nm, c = 0.522 6(3)nm for CeO2 doped zirconia and a = 0.360 2(8)nm, c=0.517 9(1) nm for Y2O3 doped zirconia. respectively. In each uni t cell, there are two kinds of equivalent positions, i.e. 2b and 4d, which are occupied by Zr4+, M(M= Y3+, Ce4+) cations and O2- anions, respectively. The crystallographic correlation among the cubic, tetragonal and monoclini c structures of ZrO2 is discussed.