High-temperature XRD study of the tetragonal-cubic phase transition in nanocrystalline, compositionally homogeneous ZrO2-CeO2 solid solutions

FUENTES R.O.; LAMAS, D.G.; ACUÑA, L.M.; FÁBREGAS, I.O.; FERNÁNDEZ DE RAPP, M.E; WALSOE DE RECA, N.E.; CRAIEVICH A.F.

Activity Report of the Brazilian Synchrotron Light Laboratory

Año: 2006 p. 680 - 681

   The aim of this work is to study the tetragonal-cubic phase transition as function of temperature on nanocrystalline powders of ZrO2 -50, 60 and 65 mol% CeO2 by high-temperatureX-ray diffraction (HT-XRD) employing synchrotron radiation. The evolution of the (112) peak with temperature was studied in all systems. The (112) peak is a characteristic reflection of the tetragonal phase, while it is a forbbiden reflection in a fluorite-like structure of the cubic phase. This reflection is related to the displacement of the oxygen anions. By monitoring of this peak it was possible to discriminate between tetragonal and cubic phases. This investigation is very important from a technological point of view, since these materials are employed at high temperatures (600-1000ºC) in Solid-Oxide Fuel Cells. A research project concerning the preparation and evaluation of SOFCs operated with hydrocarbons (methane, natural gas, biogas, etc.) is in progress at CINSO. ZrO2-CeO2 solid solutions are used for anodes, since they have excellent catalytical properties for methane oxidation