Phase evaluation and temperature stability in BaTiO3-BiScO3 modified Na0.5Bi0.5TiO3 lead-free ceramics

Structural and dielectric thermal stability in (1- 2x)Na0.5Bi0.5TiO3 (NBT)-xBaTiO(3) (BT)-xBiScO(3) (BS) for x = 0.01, 0.03, 0.05, 0.07, and 0.09 lead-free ceramics were first investigated. X-ray diffraction studies revealed composition-driven phase transitions in NBT-BT-BS ceramics, wherein the crystal structure changed from rhombohedral to a mixed phase of cubic and tetragonal with increasing x. Dielectric measurements showed a low-temperature dielectric dispersion and a high-temperature dielectric maxima for all the ceramic samples. This was attributed to the presence of two types of polar nano region (PNR), such as low-temperature PNRs and high-temperature PNRs. The composition of x = 0.05 exhibited a relatively high permittivity of 3250 at 250 degrees C (10 kHz) maintaining thermal stability varying no more than +/- 15% from temperature range of 168 to 400 degrees C. These results suggest that the addition of BT-BS to the NBT ceramics can also be suitable candidates for high-temperature capacitor applications.