The Effect of the Firing Conditions on the Properties of Barium Strontium Titanate Powders Prepared by Sol-Gel Combustion Method Using Citric Acid as Fuel

Abstract

Barium strontium titanate (Ba0.7Sr0.3TiO3; BST) powders were prepared via sol-gel combustion method using citric acid as fuel. The molar ratio of sol powder: fuel = 1:1. All of the samples were calcined at 450–950°C for 2, 3 and 4 hours. The crystallinity of the powders was improved by increasing the calcination temperature indicated by the increasing of the perovskite peak intensity from the X-rays diffraction analysis. The pure perovskite phases were crystalline at temperature 750°C with calcination time 2, 3 and 4 hours, after that BST powders were applied with acid treatment process. The XRD result showed that the pure perovskite phase without the phase of pyrochlore in all of the samples.BST is in cubic structure, corresponding to JCPDS 34–0411. The morphology and microstructure of synthesized BST powders were analyzed by a scanning electron microscope (SEM). The particles were agglomerated, spherical shape and were larger corresponding with the increasing of calcination temperature and dwelling time. The average of particle size was about 50–115 nm.