Navegando por Palavras-chave "Propriedades Dielétrico"

Agora exibindo 1 - 1 de 1
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Preparação, Caracterização E Estudo Das Propriedades Dielétricas Dos Materiais Cerâmicos De Cacu3Ti4O12 Dopados Com Magnésio
    (Universidade Federal de São Paulo (UNIFESP), 2017-02-22) Arruda, Leonardo Goncalves [UNIFESP]; Antonelli, Eduardo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Recently, CaCu3Ti4O12 (CCTO) has attracted significant attention due its high permittivity. Although it presents high value for tangent of loss, which has limited its utilization in technological industries. In this work, CCTO pure and doping with magnesium (Mg) were sintered by reaction ceramic powders solid reaction. The powders were initially characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), density by Archimedes and Impedance Spectroscopy (IS). The analysis with XRD showed that phase of CCTO were obtained in both sample. A displacement was observed at main peak of pure sample; however, the same result was not observed for the doped sample. Studies by SEM indicate that process growth and densification of the pure sample is related to the sintering time, however the same result is not observed for the doping sample. These results were associated with the fact that Cu and Mg had the same ionic radius. By the SI technique, it was verified that microstructure of the material is not able to explain the origin of GDC and that grain boundaries and grain are responsible for CCTO dielectric constant. Although the Internal Barrier Layer Capacitor (IBLC) model describes some presented results, it was inefficient in describing the electric behavior of the CCTO. After all, the IBLC model not be able explain the increase in the dielectric constant accompanied by the increase in the loss tangent. However, the Nanosized Barrier Layer Capacitor (NBLC) and grain domain models can better explain the electrical behavior of the samples. Since the essences of the two models are similar, they are based on planar defects. However, the NBLC presented with the best model to explain the electric response of the CCTO, as discussed.