Mechanically Induced Zone Darkening of Alumina/Ceria-Stabilized Zirconia Composites
| Autor: | SERGO, VALTER, SCHMID, CHIARA, MERIANI S, EVANS A. G. |
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| Přispěvatelé: | Sergo, Valter, Schmid, Chiara, Meriani, S, Evans, A. G. |
| Jazyk: | angličtina |
| Rok vydání: | 1994 |
| Předmět: |
Cerium compounds
Alumina X ray spectroscopy Cerium Bending (deformation) Diffusion Photoelectron spectroscopy Residual stresses Phase transitions Alumina Bending (deformation) Ceramic materials Cerium Cerium compounds Diffusion Phase transitions Photoelectron spectroscopy Reduction Residual stresses X ray spectroscopy Zirconia Ceramic materials Zirconia Reduction |
| Popis: | Alumina/ceria-stabilized zirconia bars tested in four-point bending exhibited deformation bands on the tensile side due to localized tetragonal-to-monoclinic transformation. These bands became increasingly darker and were fully visible some weeks after the bending experiment. XPS spectra revealed that the darker regions are characterized by a higher concentration of cerium in the +3 oxidation state, as opposed to other undeformed regions, in which +4 is the predominant oxidation state. A numerical calculation established that residual stresses exist in the deformation bands. It is suggested that these stresses facilitate the reduction of cerium with the gradient in stress motivating the diffusion of oxygen vacancies. |
| Databáze: | OpenAIRE |
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