The Relationship of Phase Structure, Microstructure and Electrical Properties of BNT-BT-BST Ceramic

Abstract

(0.935-x)Bi_0.5Na_0.5TiO₃-0.065BaTiO₃-xBa(Sn_0.1Ti_0.9O₃) ceramics with x(BST) = 0, 0.01, 0.03, 0.05, 0.07, 0.10, and 0.15 wt.% were prepared by a solid-state reaction method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties analysis of BNT-BT-x(BST) ceramics were also studied. The phase structures of BNT-BT-x(BST) ceramics with difference of x(BST) contents were characterized by X-ray diffraction method (XRD). It was found that the samples showed coexistent phases between rhombohedral and tetragonal morphotropic phase boundary (MPB). The grain growth is inhibited with increase of x(BST) contents, which showed the average gain size decreased from 0.94 to 0.63 µm. The phase transition with the first anomaly temperature at the lower temperature (T_FA) gradually decreased from 160 to 74 °C, and then tend to increase from 74 to 151 °C. Meanwhile, the second broad dielectric constant peak at higher temperature (T_SA) tended to increase first, and then decrease from 307 to 281 °C. Both T_FA and T_SA exhibit an obvious dependence on the frequency, which showed the relaxor ferroelectric behavior. The highest density (ρ = 5.79 ± 0.15 g/cm³), recoverable energy storage density (W_rec= 0.28 J/cm³) and energy storage efficiency (η = 53.85%) and the piezoelectric coefficient (d₃₃*= 450 pm/V.) was found in the composition of x(BST) = 0.05 wt.%.

Keywords:

• Phase structure
• ferroelectric properties
• piezoelectric properties
• energy density properties

Acknowledgments

This work was supported financially by The National Science, Research and Innovation Fung (NSRF) through Naresuan University (R2564B001). The authors wish to thank the Department of Physics, Faculty of Science and Technology, Pibulsongkram Rajabhat University for supporting facilities.