Structure and dielectric properties of (1-x)Bi 0.5 Na 0.5 TiO 3-x BaTiO 3 piezoceramics prepared using hydrothermally synthesized powders

• Published in: Royal Society open science Vol. 8; no. 7; p. 202365
• Main Authors: Nesterović, Andrea, Vukmirović, Jelena, Stijepović, Ivan, Milanović, Marija, Bajac, Branimir, Tóth, Elvira, Cvejić, Željka, Srdić, Vladimir V
• Format: Journal Article
• Language: English
• Published: England 01.07.2021
• Subjects: perovskite; hydrothermal synthesis; sintering; BNT-BT; dielectric properties
• ISSN: 2054-5703; 2054-5703
• DOI: 10.1098/rsos.202365

The influence of different processing parameters and various Ba addition (up to 10 mol%) on the structure and dielectric properties of Bi Na TiO -BaTiO (BNT-BT) ceramics was investigated. The powders were hydrothermally synthesized in the alkaline environment at 180°C for different time periods. X-ray diffraction confirmed the presence of dominant rhombohedral Bi Na TiO phase and a small amount of secondary pyrochlore Bi Ti O phase in the pure BNT powders. In addition, one-dimensional Na Ti O structure was also observed in the powder hydrothermally treated for a long time (i.e. 48 h). The amount of secondary pyrochlore phase in the BNT-BT powders increases with the increase of Ba content. The synthesized powders were pressed into pellets and finally sintered at various temperatures up to 1150°C. High density (more than 90%TD) was obtained in all BNT-BT sintered samples. Optimal sintering parameters were chosen in order to obtain dense ceramics with the optimal phase composition. The temperature dependence of dielectric properties for the BNT-BT ceramics was also studied. Relaxor behaviour of BNT-based ceramics and broad transition peaks are evident in all samples. Dielectric constant up to 400 as well as an acceptable low dielectric loss at temperatures lower than 200°C were obtained in BNT-BT ceramics.