Structural and Dielectric Properties of (Bi1/2Na1/2)TiO3-WO3 Ceramics

Polycrystalline samples of lead-free (1-x)(Bi1/2Na1/2)TiO3-xWO(3) with ( 0 <= x <= 0.10) were prepared using a high-temperature solid-state reaction method. X-ray diffraction analyses indicated the formation of single-phase orthorhombic structure. It is seen that addition of WO3 to (Bi1/2Na1/2)TiO3 changes the crystal symmetry. Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds. The values of apparent particle size and lattice strain are seen to increase with the increasing WO3 content. Temperature dependence of dielectric constant showed that the addition of WO3 to (Bi1/2Na1/2)TiO3 shifts phase transition temperature as well as depolarization temperature to higher temperature side. Permittivity data showed a low temperature coefficient of capacitance (T-CC < 4 %) up to 100 degrees C.