Synthesis and dielectric properties of Na0.5Bi0.5Cu3Ti4O12 ceramic by molten salt method

Na0.5Bi0.5Cu3Ti4O12 (NBCTO) powder was prepared by molten salt method at 700, 750, 800, and 850 °C in NaCl–KCl flux salts, respectively. X-ray diffraction data revealed that the main NBCTO phase of powder was synthesized at a low temperature of 700 °C for 2 h in NaCl–KCl flux, which was reduced by about 250 °C compared with the conventional solid-state reaction method. The evolution of the microstructure was observed by scanning electron microscopy, and the dielectric properties of NBCTO ceramics affected by sintering temperature and sintering time were studied in detail in this paper. The complex impedance plots were also employed to analyze the dielectric properties of NBCTO ceramics. The average grain size of the sintered ceramic increased with the increase in sintering temperature, which lead to the increased dielectric constant of the NBCTO ceramic, whereas the sintering time has affected the dielectric constant slightly. A high dielectric constant of more than 104 and a low loss tangent (tanδ) of 0.06 (at 10 kHz) were obtained for the NBCTO ceramic sintered at 1040 °C for 12 h.