Dielectric Properties and Microstructure of Nb‐Co Codoped BaTiO ₃ –(Bi _0.5 Na _0.5 )TiO ₃ Ceramics

Abstract

X‐ray diffractometry, scanning electron microscopy, transmission electron microscopy, and an impedance analyzer were used to examine the Nb–Co codoping effects on the densification, crystalline phase, microstructure development, and dielectric–temperature characteristics of BaTiO 3 –(Bi 0.5 Na 0.5 )TiO 3 ceramics. The results indicate that the Curie temperature shifted to a higher temperature (above 140°C) by adding BNT. The dielectric constant–temperature (ɛ– T ) curve broadened at the Curie temperature due to the small grain size (0.3–0.4 μm). A core‐shell structure was developed, which is helpful to flatten the ɛ– T curve of BaTiO 3 ceramics at high temperatures.