Phase Formation and Microstructure of Barium Zirconate Ceramics Prepared Using the Combustion Technique

Abstract

Abstract The effect of calcination temperatures (900–1400°C) and sintering temperatures (1400–1650°C) on phase formation and microstructure of perovskite barium zirconate (BaZrO 3 ) powders and ceramics was investigated. The BaZrO 3 powders were prepared using the combustion technique. The phase purity, crystal structure and microstructure of samples were examined using differential thermal analysis (DTA), thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that BaZrO 3 samples indexed in a cubic structure. The percentage phase purity of perovskite increased with an increase in the calcination temperatures as expected. The purity of perovskite powders was obtained above 1350°C and the purity phase of ceramics was detected in all samples. The SEM results indicated that the particle size and grain size of samples increased with the increase of calcination and sintering temperatures. The shrinkage of ceramics increased as the sintering temperatures increased. The optimized heat treatment permits sintering a ∼97% highly dense barium zirconate sample at 1600°C for only 2 h. Keywords: Combustion techniquenanosized particlesdensitycubic perovskite phase Acknowledgments This work was supported financially by the Thailand Research Fund (TRF), Commission on Higher Education (CHE). Thanks also goes to the Science Lab Center, Faculty of Science, Naresuan University for support facilities. Acknowledgements also given to Mr. Don Hindle and Assoc. Prof. Dr. Mary Sarawit, for their helpful correction of the manuscript.