The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics

Abstract

Ferroelectric ceramic barium strontium titanate (Ba0.77Sr0.23TiO3), BST, was prepared by solid-state reactions using starting powders of barium carbonate (BaCO3), strontium carbonate (SrCO3) and titanium dioxide (TiO2-anatase). Non-activated and mechanically activated mixtures with high-energy planetary ball mill (0, 5, 10, 20, 80 and 120 minutes) were sintered at 1100, 1200, 1300 and 1400 °C for two hours in air. The maximum value of ceramic density is about 86.20% TG. X-ray diffraction analysis was used to obtain information on the phase composition, as well as determining the influence of mechanical activation on the half height width of the diffraction lines (111) BST isothermally sintered samples at 1400 °C during two hours. Defects and the beginning process of sintering on the microstructure were investigated by scanning electron microscopy (SEM). Electrical measurements (loss tangent of the angle, Nyquist diagrams and influence the activation time dependence of XC = f (log ν)) are made of ceramics sintered at 1400 °C for two hours.