Combined positron-annihilation and structural studies of hydrothermally grown zirconia

Nanoporous zirconia is used in gas sensors and as a membrane in high-temperature fuel cells. In the present work, positron annihilation spectroscopy and transmission electron microscopy (TEM) were performed on pure zirconia-sintered nanopowders, to determine the porosity. The ortho-positronium annihilation parameter R of zirconia samples, treated at 800°C and 700°C and annealed in oxygen–nitrogen atmosphere with different O2 contents, were obtained. The photoluminescence, positron annihilation spectroscopy, and TEM studies show presence of defects in all samples. Furthermore, the positron annihilation studies indicate a presence of large free volumes (of the order of few atomic units, at least), open towards the nanocrystals surface what was confirmed by TEM observations which detected a few types of defects such as voids within ≈2–4 interplane distances, stacking faults, terraces and point defects.

[1]  G. Ottaviani,et al.  Formation of vacancy clusters and cavities in He-implanted silicon studied by slow-positron annihilation spectroscopy , 2000 .

[2]  G. Teufer,et al.  The crystal structure of tetragonal ZrO2 , 1962 .

[3]  J. Grabis,et al.  Intrinsic defect related luminescence in ZrO2 , 2011 .

[4]  M. Finnis,et al.  A stabilization mechanism of zirconia based on oxygen vacancies only , 2002, cond-mat/0206080.

[5]  A. Burggraaf,et al.  Zirconia as a support for catalysts: Evolution of the texture and structure on calcination in air , 1990 .

[6]  K. Trueblood,et al.  The crystal structure of baddeleyite (monoclinic ZrO2) , 1959 .

[7]  H. Gesser,et al.  Aerogels and related porous materials , 1989 .

[8]  J. C. Ray,et al.  Chemical synthesis and structural characterization of nanocrystalline powders of pure zirconia and yttria stabilized zirconia (YSZ) , 2000 .

[9]  J. Kansy.  Microcomputer program for analysis of positron annihilation lifetime spectra , 1996 .

[10]  A. Zecca,et al.  A new electrostatic positron beam for surface studies , 1998 .

[11]  Wuzong Zhou,et al.  Imaging the Pore Structure and Polytypic Intergrowths in Mesoporous Silica , 1998 .

[12]  D. Pliszka,et al.  Positron annihilation study of vacancy-like defects related to oxygen precipitates in Czochralski-type Si , 2001 .

[13]  Larisa Grigorjeva,et al.  Zirconia Based Nanomaterials for Oxygen Sensors – Generation, Characterisation and Optical Properties , 2007 .

[14]  A. Speghini,et al.  Structure−Luminescence Correlations in Europium-Doped Sol−Gel ZnO Nanopowders , 2008 .

[15]  Wuzong Zhou,et al.  Disruption of extended defects in solid oxide fuel cell anodes for methane oxidation , 2006, Nature.

[16]  J. Kuriplach,et al.  Positron Lifetimes in Zirconia-Based Nanomaterials , 2008 .

[17]  Ellen Ivers-Tiffée,et al.  Principles of solid state oxygen sensors for lean combustion gas control , 2001 .

[18]  A. Karbowski,et al.  Testing an Ortec Lifetime System , 2010 .

[19]  J. Ding,et al.  Nanopowders Synthesized by Mechanochemical Processing , 2001 .

[20]  Grzegorz P. Karwasz,et al.  Positron-annihilation and photoluminescence studies of nanostructured ZrO2 , 2010 .

[21]  Tadafumi Adschiri,et al.  Hydrothermal technology for nanotechnology , 2007 .

[22]  E. C. Subbarao,et al.  Zirconia - an overview , 1981 .

[23]  R. M. Cannon,et al.  Toughening of brittle solids by martensitic transformations , 1986 .

[24]  J. Gole,et al.  Unique Properties of Selectively Formed Zirconia Nanostructures , 2006 .

[25]  G. Gehring,et al.  Mechanical alloying: a route to room-temperature Ferromagnetism in bulk Zn1-xMnxO , 2004 .

[26]  S. Seal,et al.  Mechanisms of room temperature metastable tetragonal phase stabilisation in zirconia , 2005 .

[27]  Mingmei Wu,et al.  Formation mechanism of CaTiO3 hollow crystals with different microstructures. , 2010, Journal of the American Chemical Society.

[28]  H. Lipson.  Crystal Structures , 1949, Nature.

[29]  K. Lynn,et al.  Characterization of defects in Si and SiO2−Si using positrons , 1994 .

[30]  Wuzong Zhou.  Microscopic study of crystal defects enriches our knowledge of materials chemistry , 2008 .

[31]  D. K. Smith,et al.  The crystal structure of baddeleyite (monoclinic ZrO2) and its relation to the polymorphism of ZrO2 , 1965 .

[32]  S. Sōmiya,et al.  Hydrothermal Zirconia Powders: A Bibliography , 1999 .

[33]  J. Cizek,et al.  Positron annihilation study of yttria-stabilized zirconia nanopowders containing Cr2O3 additive , 2011 .

[34]  K. Smits,et al.  Advanced nanocrystalline ZrO2 for optical oxygen sensors , 2009, 2009 IEEE Sensors.

[35]  Alan C. Lloyd,et al.  THE POWER PLANT IN YOUR BASEMENT , 1999 .

[36]  J. Fergus.  Electrolytes for solid oxide fuel cells , 2006 .

[37]  L. Lillo,et al.  Structure and optical characterization of photochemically prepared ZrO2 thin films doped with erbium and europium , 2008 .

[38]  G. Ottaviani,et al.  Structural evolution in Ar+ implanted Si-rich silicon oxide , 2003 .

[39]  G. Ottaviani,et al.  Porosity in low dielectric constant SiOCH films depth profiled by positron annihilation spectroscopy , 2004 .

[40]  G. Consolati.  Positronium trapping in small voids: Influence of their shape on positron annihilation results , 2002 .

[41]  Juan Rodriguez-Carvaj,et al.  Recent advances in magnetic structure determination neutron powder diffraction , 1993 .

[42]  C. Leonelli,et al.  Main development directions in the application of microwave irradiation to the synthesis of nanopowders , 2007 .