Preparation and Dielectric Properties of WO3-Doped Small-Grained BaTiO3 Ceramics

Abstract

BaTiO3 ceramics with small grain size (<2µm in diameter) was prepared from fine powder by doping WO3 as an inhibitor of grain growth. Average grain size, bulk density (%) of theoretical, dielectric constant (20°C) and tan δ for the BaTiO3 ceramics doped with 0.5 mole% WO3 and sintered at 1300°C for 5 h in O2 are 1.2µm, 94%, 3400 and ≃2%, respectively. The dielectric constant depends strongly on the grain size below the Curie temperature, whereas it is weakly dependent on the grain size above the Curie temperature. The Curie temperature decreased from 120°C to 110°C when WO3 content varied from 0 to 1.0 mole%. The dielectric variation with ambient temperature is much less than that of the undoped BaTiO3 ceramics. The dielectric properties of the WO3-doped BaTiO3 ceramics have been found much superior to those of the undoped conventional one.