Exploring the dielectric properties, glass ability and ferroelectric phases in the BaO-Bi2O3-TiO2-B2O3-Al2O3 system

In this study, Bi- and Ti-rich glasses have been designed and investigated for the development of ferroelectric glass-ceramics (GCs). The glass formation range, the structure of the glass network and the crystalline phases obtained in the glass-ceramics were explored. Glass compositions within the xBaO-(90-x)(40Bi2O3-25TiO235B2O3)-10Al2O3 system were synthesized through rapid press quenching of the melt, with a controlled melting temperature of 1000 degrees C. Raman spectroscopy was carried out to investigate the impact of Bi2O3, TiO2 and BaO on the arrangement of the structural units in these glasses. Subsequent thermal treatment in the temperature range of 500-700 degrees C led to the formation of glass-ceramics containing the ferroelectric Bi4Ti3O12 crystal phase in all compositions. Notably, glass-ceramics containing 10-16 mol% of BaO exhibited a single Bi4Ti3O12 crystal phase upon complete crystallization. The microstructure and temperature-dependent dielectric properties of glasses and GCs were investigated as a function of the Ba content. The permittivity epsilon r of the glasses is quite high compared to other glass systems, ranging between 22 and 28, and it is greatly increased in the crystallized samples (up to 70). Furthermore, no phase transitions up to 300 degrees C are observed, especially in GCs with a single Bi4Ti3O12 crystal phase, making these materials strong candidates for energy storage dielectrics. The samples developed in this study demonstrate the potentiality of obtaining piezoelectric glass-ceramics in network formerpoor matrices.