A. Adamski, P. Jakubus, Z. Sojka
2006
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0
Influential Citations
17
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Journal
Nukleonika
Abstract
Zirconium dioxide, owing to its mechanical, thermal and chemical properties is an attractive ceramic material of various applications, which has received a great deal of research interest [14, 21, 29]. Upon chemical and textural valorization, it is also frequently used as catalyst or catalyst support [12, 22, 28]. In the latter context, zirconia may serve as a paramount example of strong dependence of the surface properties (and related catalytic activity) on the bulk structure, controlled by the nature of its polymorphic form [19]. Preparation of ZrO2 by conventional precipitation from aqueous solutions of the zirconyl salts leads usually to a mixture of the stable monoclinic m-ZrO2 and metastable tetragonal t-ZrO2 forms. However, the phase transformation between the monoclinic and the tetragonal polymorph, due to the large volume change (ca. 47%), prevents the unique properties of bare zirconia to be used in practice directly. Such disruptive phase transition can be suppressed by stabilization of t-ZrO2 either via appropriate cationic doping [14] or by tailoring the size of particles below the critical value of r0 ~ 30 nm, which gives rise to so-called TZP (tetragonal zirconia polycrystals) ceramic [13]. The resultant nanostructured t-ZrO2 exhibits distinctly different properties in comparison to the coarse-grained m-ZrO2 and t-ZrO2. Therefore, the use of appropriate preparation procedures, leading to desired form of the zirconium oxide, is required for specific applications [7, 26]. A common route for the preparation of zirconia consists in precipitation of hydrous gel with ammonia from zirconyl salt solutions and subsequent calcination Synthesis of nanostructured tetragonal ZrO2 of enhanced thermal stability Andrzej Adamski, Pawel Jakubus, Zbigniew Sojka