Effect of Ta2O5 Doping on the Microstructure and Dielectric Properties of BaTiO3 Based Ceramics

Abstract

The main focus of the research was to correlate composition and sintering parameters with the microstructure and dielectric properties of Ta2O5 doped BaTiO3 ceramics. The samples were sintered using both single and two-stage sintering techniques. Thereafter SEM and XRD techniques were used to examine the structure of the samples with a particular focus on the incorporation of Ta5+ ions into the BaTiO3 crystal lattice. The  SEM analysis focused on measuring the grain size and investigating the grain size distribution of the sintered samples. Finally, the dielectric properties were analysed and the relationship between the properties and structure of the doped BaTiO3 was established. From the research it can be stated that two-stage sintering yielded the best dielectric properties. The best stable value of the room temperature dielectric constant (k) of 19000 was obtained for the 1.5 mole % Ta2O5 doped BaTiO3 sample sintered at 13200C for 0hrs and 12800C for 6hrs, due to the combination of a high percent theoretical density (%TD) and optimum grain size. At a temperature range of 300 to 600C, this combination of composition and sintering parameters yielded a dielectric constant in the range of 18000–19000.