Crystallization and growth morphology of barium titanate and fresnoite from a glass with the composition 20.1Na2O·23.1BaO·23TiO2·9.8B2O3·21SiO2·3Al2O3

Abstract

A glass with the composition 20.1Na₂O·23.1BaO·23TiO₂·9.8B₂O₃·21SiO₂·3Al₂O₃ (in mol%) was synthesized using a traditional glass melting technique. Its thermal properties were characterized by differential thermal analysis (DTA), and appropriate time–temperature schedules were applied in order to prepare glass-ceramics containing barium titanate. X-ray diffraction (XRD) analysis showed the formation of cubic barium titanate and fresnoite at an annealing temperature of 650 °C and for times t ≥ 3 h, while annealing for 1 h resulted in the sole crystallization of barium titanate. Supplying longer crystallization times resulted in the additional formation of increasing fresnoite concentrations. The crystallization behavior of the glass is characterized using electron microscopy techniques, i.e. energy dispersive X-ray spectroscopy (EDXS) and electron backscatter diffraction (EBSD), which reveal the simultaneous growth of fine, densely-branched barium titanate and fresnoite crystals.