PAC Characterization of Nontransformable Tetragonalt′ Phase in Arc-Melted Zirconia-2.8 mol% Yttria Ceramics
Autor: | Patricia C. Rivas, Agustín M. Rodríguez, Sergio R. Mintzer, María C. Caracoche, Alberto F. Pasquevich |
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Rok vydání: | 2001 |
Předmět: | |
Zdroj: | Journal of the American Ceramic Society. 84:188-192 |
ISSN: | 1551-2916 0002-7820 |
DOI: | 10.1111/j.1151-2916.2001.tb00629.x |
Popis: | Tetragonal compact bodies obtained by quenching from the melt a ZrO 2 -2.8 mol% Y 2 O 3 commercial powder have been investigated between room temperature and 1150°C, using mainly perturbed angular correlations spectroscopy. The resulting nontransformable t' phase observed by optical micrography is characterized at nanoscopic level by a hyperfine interaction describing defective and disordered Zr 4+ neighborhoods very different from those of the regular tetragonal phase. A small amount of remaining Zr 4+ sites corresponds to a scarcely distorted tetragonal structure. As the compacts are heated, two processes activate: the movement of vacancies and the gradual and irreversible conversion of t' defective sites into less defective ones, probably resulting from oxygen absorption. |
Databáze: | OpenAIRE |
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