Effect of Calcination Temperature on the Microstructures of Barium Titanate Hafnate Nanopowders Prepared by the Sol-gel Process

Abstract

Barium titanate hafnate (BaHf_0.1Ti_0.9O₃, short for BHT) powders were prepared by sol-gel process at different calcination temperatures. Thermal analyses (TG-DTA), x-ray diffraction (XRD) and transmission electron microscopy (TEM) were performed. It is found that there are no exothermic peaks or endothermic vales above 700°C in correspondence with new reactions. Therefore, the calcination temperature should be higher than 700°C to facilitate the formation of BHT. The XRD spectra suggest that the powders possess perovskite structure without impurity. When the calcination temperature increased from 700 to 900°C, the reflection peaks became sharper and stronger. The XRD and TEM results reveal that the average size of powder increases with the increasing calcination temperature.

Keywords:

• Barium titanate hafnate
• nanopowder
• ferroelectric
• sol-gel

Acknowledgments

This work has been supported by the Natural Science Foundation of Chongqing, China (Grant No. CSTC2011BA4027), National Natural Science Foundation of China (Grant No. 51102288) and Open Research Fund of State Key Laboratory of Electronic Thin Films and Integrated Devices (UESTC) (KFJJ201104).