Hydrothermal synthesis, microstructure and electrical properties of (1- x)(Na0.5Bi0.5)TiO3-xBaTiO3 ceramics

In this paper, the synthesis of ferroelectric (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3 ceramics of different compositions (x=0.00, 0.03, 0.05, 0.06, 0.07, 0.08, 0.1wt%) around the morphotropic phase boundary (MPB) by hydrothermal reaction technique has been reported. The XRD patterns recorded at room temperature proved the perovskitetype structure formation. Furthermore, the analysis revealed the phase transition from the rhombohedral structure (x = 0) to tetragonal structure (x ⩾ 0.08). Using Rietveld refinement method which allow us to verify the morphotropic phase boundary (MPB) at x=0.05-0.07. From the Scanning Electron Microscopy (SEM) analysis, have revealed uniform distribution of grains and change in grain size with the increase in BaTiO3 concentration. Presence of functional groups has been determined by Raman Spectroscopy at roomtemperature. The dielectric properties of the ceramics were studied in the frequency range of 1KHz–1MHz from room temperature to 600 °C. The broad dielectric peak and frequency dispersion demonstrate the relaxor behavior of ceramics. The dielectric constant (er), transition temperature (Tm), depolarization temperature (Td) and diffusive factor (γ) are determined to be comparatively good and tabulated for 100 kHz. These measurements imply that BaTiO3 addition to NBT-xBT ceramics can be admitted as a potential lead free ceramic system in piezoelectric devices.