Effect of sintering temperature on the microstructure and electrical properties of (Na0.5Bi0.5)TiO3 processed by the sol-gel method.

Autor: Mesrar, M., Lamcharfi, T., Echatoui, N-S., Abdi, F.
Zdroj: Journal of Sol-Gel Science & Technology; Sep2022, Vol. 103 Issue 3, p820-831, 12p
Abstrakt: (Na0.5Bi0.5)TiO3 lead free ceramics have been synthesised by conventional sol-gel reaction method. The crystalline phase of calcined ceramics was studied at room temperature using X-ray diffraction. Rietveld refinement of the XRD measurements by FullProf showed that the samples have a rhombohedral structure with a space group R3c. In this study, NBT ceramics were sintered at different temperatures of 1000 °C, 1050 °C and 1100 °C for a period of 4 h. The sintering temperature was determined to be 1100 C, and the effect of sintering temperature on grain size was interpreted using dynamic crystal growth theory and, consequently, the electrical behaviour was also examined. The dielectric properties of these ceramic products were examined at different temperatures over a wide frequency range using an impedance analyser. It was found that the dielectric constant and dielectric loss decreased with increasing measurement frequency. The resulting ceramics have a large maximum dielectric permittivity at 320 °C and a dispersive permittivity at high temperatures. The exposant critique ɤ of the relationship between the dielectric constant and temperature ε rmax / ε r vs (T-Tm)ɣ) has been calculated with precision for NBT relaxor ferroelectrics at different frequencies. The (Na0.5Bi0.5)TiO3 sample exhibits a diffuse ferroelectric behaviour. Highlights: Lead-free piezoelectric ceramics (Na0.5Bi0.5)TiO3 are formed using the sol-gel method. The ceramics have a pure perovskite structure with the rhombohedral phase. Effects of sintering temperature on the electrical properties were investigated. The NBT exhibits ferroelectric relaxer behavior. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index