View in EDS

Investigation of mechanically stimulated solid phase polymorphic transition of zirconia

Saved in:

Bibliographic Details
Title:	Investigation of mechanically stimulated solid phase polymorphic transition of zirconia
Authors:	Kuznetsov, Peter N.^1,2 kuzpn@icct.ru, Kuznetsova, Ludmila I.¹, Zhyzhaev, Anatoly M.¹, Kovalchuk, Vladimir I.³ vkovalch@pitt.edu, Sannikov, Alexander L.², Boldyrev, Vladimir V.^4,5 boldyrev@nsu.ru
Source:	Applied Catalysis A: General. Jan2006, Vol. 298, p254-260. 7p.
Subjects:	Zirconium oxide, Catalysts, Evaporation (Chemistry), Pressure
Abstract:	Abstract: The effect of mechanical treatment of monoclinic zirconia in a high-energy centrifugal planetary ball mill and in a vibrating ball mill, with much less mechanical impact, on its crystallographic characteristics and texture was investigated as a function of the applied mechanical load and the treatment medium. Mechanical treatment in a high-energy planetary ball mill was shown to result in particle desintegration into small crystallites of less than 20nm in size, accumulation of strains, and fast solid phase transition to metastable nano-structured tetragonal form. The rate of the phase transition depended on the treatment medium. The transition completed during 15min with dry-powdered ZrO2. The presence of water retarded the phase transition. Mechanical treatment in a vibrating mill resulted in particle desintegration into crystallites of 38–42nm in size, accumulation of strains, and gradual amorphization of the crystalline structure; however, the transformation to the tetragonal form did not occur. The factors favored the solid phase polymorphic transition of a stable form of ZrO2 into metastable one are discussed. A high-temperature and a high pressure, which are developed in local sites of the solid under pulse mechanical impact of high-energy, provide thermodynamically favorable conditions and kinetic acceleration of the phase transition. The effect of the metastable form of ZrO2 stabilization originates from the small size of the crystallites as a result of particle desintegration. [Copyright &y& Elsevier]
	Copyright of Applied Catalysis A: General is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database:	Engineering Source

Description
Abstract:	Abstract: The effect of mechanical treatment of monoclinic zirconia in a high-energy centrifugal planetary ball mill and in a vibrating ball mill, with much less mechanical impact, on its crystallographic characteristics and texture was investigated as a function of the applied mechanical load and the treatment medium. Mechanical treatment in a high-energy planetary ball mill was shown to result in particle desintegration into small crystallites of less than 20nm in size, accumulation of strains, and fast solid phase transition to metastable nano-structured tetragonal form. The rate of the phase transition depended on the treatment medium. The transition completed during 15min with dry-powdered ZrO2. The presence of water retarded the phase transition. Mechanical treatment in a vibrating mill resulted in particle desintegration into crystallites of 38–42nm in size, accumulation of strains, and gradual amorphization of the crystalline structure; however, the transformation to the tetragonal form did not occur. The factors favored the solid phase polymorphic transition of a stable form of ZrO2 into metastable one are discussed. A high-temperature and a high pressure, which are developed in local sites of the solid under pulse mechanical impact of high-energy, provide thermodynamically favorable conditions and kinetic acceleration of the phase transition. The effect of the metastable form of ZrO2 stabilization originates from the small size of the crystallites as a result of particle desintegration. [Copyright &y& Elsevier]
ISSN:	0926860X
DOI:	10.1016/j.apcata.2005.10.002