Hydrothermal Synthesis of Oxide and Carbonate Powders of(l-x)(Nao.5Bio.5)Ti03.xBaTi03 Ceramics

摘要

In this study,the synthesis of ferroelectric(1-x)(Na_(0.5)Bi_(0.5))TiO_(3-x)BaTiO3 ceramics have been successfully prepared via a hydrothermal process,using bismuth oxide and barium carbonate.The characterization is done using X-ray diffraction,scanning electron microscope,Raman spectroscopy and dielectric measurements.The XRD patterns recorded at room temperature confirmed the formation of a single phase with rhombohedral structure.There is a transformation in crystal structure from rhombohedral to coexistence of rhombohedral and tetragonal to a single tetragonal phase with the increase in BaTiO3 concentration in basic(1-x)(Na_(0.5)Bi_(0.5))TiO_(3-x)-BaTiO3 composition.From SEM microscopy,the particle sizes are estimated in the range of 5-24 μm.The analysis of both Raman and the spectral deconvolution data of our samples also indicated the distortion of(1-x)(Na_(0.5)Bi_(0.5))TiO_(3-x)BaTiO3 lattice with the addition of Ba~(2+)ion.Rietveld refinement method allows us to verify the morphotropic phase boundary at x = 0.05-0.07.The dielectric properties of the solid solution increase with a rise in Ba-Ti03 content and shows optimum value at x = 0.07 owing to the co-existence of two ferroelectric phases.Based on these results,it is proved that morphotropic phase boundary in the studied system is included in the composition x = 0.05 and 0.07.