Temperature dependence of dielectric characteristics of doped bismuth titanate ceramics

Full text: Bismuth-titanate ceramics with additives were obtained by melt quenching combined with additional heat treatment. The phase composition of selected samples in the systems Bi2O3-TiO2-SiO2, Bi2O3-TiO2-Nd2O3, and Bi2O3-TiO2-SiO2-Nd2O3 was determined by X-ray diffraction (XRD) analysis. The microstructure was observed by scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) was applied to identify the distribution of microcrystals in the matrix. The XRD data showed that the main crystalline phases in the ceramics were Bi2O3, Bi2Si05, and Bi4Ti3Oi2. SEM and EDS analyses illustrated a microstructure of various crystal morphology and different crystal composition. The main electrical characteristics of the glass-ceramic materials were measured as a function of temperature. All the investigated samples were dielectric materials with conductivity between 10-9 and 10-13 (Ωcm)-1, capacitance between 10-11 and 10-12 F, and dielectric losses tgδ between 0.02 and 0.1. A correlation was established for the synthesis method applied, the thermal history, and the microstructure and the dielectric parameters of the studied materials