Crystal structure and local order of nanocrystalline zirconia-based solid solutions

I.O. FÁBREGAS; D.G. LAMAS; L.M. ACUÑA; N.E. WALSÖE DE RECA; ALDO F. CRAIEVICH; M.C.A. FANTINI; R.J. PRADO

POWDER DIFFRACTION

JCPDS-International Centre for Diffraction Data

Lugar: Newtown Square; Año: 2008 vol. 23 p. 46 - 55

0885-7156

Crystal and local structures (long- and short-range order, respectively) of four nanocrystalline zirconia-based solid solutions, ZrO2-6 and 16 mol % CaO and ZrO2-2.8 and 12 mol %Y2O3, synthesized by a pH-controlled nitrate-glycine gel-combustion process were studied. These materials were characterized by synchrotron X-ray diffraction (XRD) and extended X-ray absorption fine structure(EXAFS) spectroscopy. Our XRD results indicate that the solid solution with low CaO and Y2O3 contents (6 and 2.8 mol %, respectively) exhibit a tetragonal crystallographic lattice, and those with higher CaO and Y2O3 contents (16 and 12 mol %, respectively) have a cubic lattice. Moreover, our EXAFS study demonstrates that thetetragonal-to-cubic phase transitions, for increasing CaO and Y2O3 contents, are both related to variations in the local symmetry of the Zr–O first neighbor coordination sphere.