Elastic, dielectric and electromechanical properties of (Bi0.5Na0.5)TiO3-BaTiO3piezoceramics at the morphotropic phase boundary region
A systematic study of the functional properties of the (1-x)(Bi0.5Na0.5)TiO3–xBaTiO3(BNT-xBT) piezoceramic system for 0.05 ≤ x ≤ 0.07 is performed. The samples are obtained through the conventional solid-state route. The expected microstructure for these compounds, with no significant dependence on...
| Autores: | , , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2016 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositório: | CONICET Digital (CONICET) |
| Idioma: | inglês |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/94222 |
| Acesso em linha: | http://hdl.handle.net/11336/94222 |
| Access Level: | Acceso aberto |
| Palavra-chave: | CERAMICS DIELECTRIC RESPONSE FERROELECTRICS PIEZOELECTRICITY https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Resumo: | A systematic study of the functional properties of the (1-x)(Bi0.5Na0.5)TiO3–xBaTiO3(BNT-xBT) piezoceramic system for 0.05 ≤ x ≤ 0.07 is performed. The samples are obtained through the conventional solid-state route. The expected microstructure for these compounds, with no significant dependence on the composition, is verified by field-emission scanning electron microscopy. The morphotropic phase boundary (MPB) is detected for x = 0.06–0.07 by means of the Rietveld analysis of X-ray diffraction data. The dielectric spectra show a frequency-independent, completely diffuse phase transition with a composition-dependent diffusivity coefficient. The depolarization temperature is effectively evaluated from pyroelectric measurements, the value being strongly dependent on the composition. A significant contribution of the extrinsic effect to elastic, dielectric and electromechanical properties is revealed for MPB BNT-xBT. The Bi3+substitution by Ba2+leads to the formation of A-site vacancies, which give rise to the enhancement of domain wall motion, as occurs in other perovskite-type piezoelectrics. Good functional properties are achieved for x = 0.07 (d33 = 180 pC/N), which are similar or even better than those obtained by complex synthesis routes. This system exhibits a remarkable stability in the permittivity that has hitherto not been reported. This fact may open the way for BNT-BT compositions to be used in specific applications in which lead-free piezoceramics have previously been employed with little success, e.g. in high power devices. |
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