Microstructural Development and Properties of (1-x) wt Ba_(0.55)Sr_(0.45)TiO_3-x wt MgO Bulk Ferroelectrics

摘要

A study was made of the relationship between the microstructure and electrical properties of the bulk ferroelectric composite materials: (100-x) wt% Ba_(0.55)Sr_(0.45)TiO_3x wt% MgO. The ferroelectric composites (x= 40, 60) were fabricated by dry pressing from two powder precursors: 1) Ba_(0.55)Sr_(0.45)TiO_3 (BST) calcined in the solid state with sol-gel MgO (Sg-MgO), and 2) hydrothermal BST and MgO calcined in the solid state. The pellets were sintered at 1250, 1350 and 1450℃. The sintered microstructure, chemistry, and phase with crystallinity was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD), respectively. The density and porosity were determined by the Archimedes technique. Dielectric properties of permittivity and loss tangent were characterized by the parallel plate capacitor method.