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Characterization of Metastable Tetragonal Forms in ZrO 2 ‐2. 8 mol% Y 2 O 3 Ceramics
Author(s) -
Rivas Patricia C.,
Caracoche María C.,
Pasquevich Alberto F.,
Martinez Jorge A.,
Rodríguez Agustín M.,
García Alberto R. López,
Mintzer Sergio R.
Publication year - 1996
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1996.tb08513.x
Subject(s) - tetragonal crystal system , materials science , metastability , vacancy defect , raman spectroscopy , zirconium , sintering , microstructure , ceramic , analytical chemistry (journal) , phase (matter) , activation energy , crystallography , redistribution (election) , mineralogy , crystal structure , chemistry , metallurgy , optics , physics , organic chemistry , chromatography , politics , political science , law
This paper deals with a perturbed angular correlation investigation of the microstructure and subsequent thermal evolution of a commercial ZrO 2 ‐2. 8 mol% Y 2 O 3 ceramic powder and of a pellet obtained upon sintering the powder at 1450°C. The perturbed angular correlation results, complemented by those of X‐ray diffraction and Raman spectrometry, indicate that the metastable tetragonal phase exhibits two hyperflne interaction forms instead of the interaction associated with the conventional t ‐ZrO 2 phase, both having different oxygen vacancy configurations around zirconium sites. While the powder sample exhibits mainly a very defective tetragonal form, the pellet exhibits a slightly distorted one as the major form. As temperature is increased, a reversible transformation between both forms occurs involving a redistribution of the oxygen vacancy. Once the transition is completed, the oxygen vacancy movement is described by a fast relaxation regime with an activation energy E act = 0. 50 ± 0. 04 eV.