Effects of Sintering Temperature on Phase Formation, Microstructure and Dielectric Properties of BNT–BT Ceramics Prepared by Combustion Technique

Abstract

Effects of sintering temperatures on phase formation, microstructure and the dielectric properties of near MPB (1-x)BNT-xBT ceramics (x = 0.06 and 0.08) were investigated. The (1-x)BNT-xBT ceramics were prepared using a combustion technique. The phase purity, crystal structure and microstructure of the samples were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pure perovskite, which consists of rhombohedral and tetragonal phases, was found in the samples sintered below 1200°C. The average grain size tended to increase with increased sintering temperature. The density and the dielectric constant at room temperature increased with increasing sintered temperature up to 1200°C, thereafter they decreased. The ceramic composition with x = 0.08 exhibited the highest density (∼ 5.80 g/cm³) and dielectric constant (∼ 2829).

Keywords:

• Phase formation
• microstructure
• dielectric properties
• BNT-BT

Acknowledgments

This work was financially supported by the Thailand Research Fund (TRF), Commission on Higher Education (CHE). The authors wish to thank the Science Lab Center, Faculty of Science, Naresuan University for equipments. Thanks are also given to Mr. Don Hindle for his help in editing the manuscript

Communicated by Professor Amar S. Bhalla