Effect of Sintering Parameters and Ta_2O_5 Doping on the Microstructure and Dielectric Properties of BaTiO_3 Based Ceramics

摘要

The main focus of the research was to correlate the composition and sintering parameters with the microstructure and dielectric properties of Ta_2O_5 (Tantalum Oxide) doped BaTiO_3 (Barium Titanate) ceramics. Ta_2O_5 was doped at three different percentages viz. 0.5, 1.0 and 1.5 mole%. The doped samples were then sintered using both single and double stage sintering techniques. Thereafter field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) techniques were used to examine the structure of the samples with particular focus on the incorporation of Ta~(5+) ions into the BaTiO_3 crystal lattice. Finally, the dielectric properties were analyzed using impedence analyzer and the relationship between the properties and structure of doped BaTiO_3 was established. From the research, it can be stated that double stage sintering yielded best dielectric properties. The best stable value of room temperature dielectric constant (k) of 19000 was obtained for 1.5 mole% Ta_2O_5 Doped BaTiO_3 sample, sintered at 1320°C for 0 minutes and 1280°C for 360 minutes due to the combination of high percent theoretical density (%TD) and optimum grain size. At a temperature range of 30°C to 60°C, this combination of composition and sintering parameters yielded dielectric constant in the range of 18000-19000.