Structure of Zirconia

The crystallographic data of the most important polymorphic structures of zirconia are listed in Table 7.6. 

Improved thermal stability by a yttria-rich coating WMy//////// MMZZZZ//M 

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The pore structures of zirconia-silica composites prepared by Shalliker et via a coating procedure... 

Shalliker, R.A. Douglas, G.K. The development of stationary phase supports for liquid chromatography I. Examination of the pore structure of zirconia-silica composites using size exclusion chromatography. J. Liq. Chromatogr. Relat. Technol. 1998, 21 (12), 1749-1765. 

The crystal structure of zirconia and the catalytic properties of SZ generally depend on the synthesis method and thermal treatment adopted. In particular zirconia crystallises in three different polymorphs characterised by monoclinic, tetragonal and cubic symmetry. Among them only the tetragonal SZ phase displays significant catalytic properties [5-7]. Unfortunately, the synthesis of the pure tetragonal polymorph is difiBcult and, in the absence of promoted oxides [8], it could be stabilised only through an accurate control of the synthesis parameters, with particular attention to the thermal treatments. 

Finnis M. W., Paxton A. T., Methfessel M. and van Schilfgaarde M., Crystal Structures of Zirconia from First Principles and Self-Consistent Tight Binding, Phys. Rev. Lett. 81, 5149 (1998). 

Simeone, D. Baldinozzi, G. Gosset, D. Le Caer, S. Mazerolles, D. L. 2005. Nano structuration of zirconia under irradiation A way to enhance the mechanical stability of zirconia layer. Reviews on Advanced Materials Science, 10 118. 

Ceramic Cutting Toois, Fig. 4 (a) schematic of transformation toughening, (b) structure of zirconia reinforced alumina... 

ZrOj-based materials have attracted considerable interest in recent decades. In a catalytic sense, they appear to have some advantages in areas of practical application over traditional oxides, such as Si02 and AljO, [1-4], More significant is the fact that additives can bring about a strong modification of the surface structure of zirconia [5-8], in which case substitution of Zr with dopant cations results in a rise in anion vacancy concentrations and conductivity. Indeed this is the basis of its redox properties and the catalytic use of stabilized zirconia. 

Gavrilov, V.Yu. and Zenkovets, G. A. (1996) Pore Structure of Zirconia and Zirconia-Titania Materials Prepared via Precipitation from Solution, Kinet. Katal., vol. 37, no. 4, pp. 617-621. 

Tomishige K, Ikeda Y, Sakaihori T, Fujimoto K (2000) Catalytic properties and structure of zirconia catalysts for direct synthesis of dimethyl carbonate from methanol and... 

Phases and Structure of Zirconia and Ceria-Zirconia Solid Solutions... 

Ceria-zirconia materials exhibit high catalytic activity and are used for exhaust gas cleaning. To understand the catalytic activity of ceria-zirconia materials, a knowledge of the phases and the crystal structure of zirconia and ceria-zirconia solid solutions is important. 

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