Growing Oriented Layers of Bi4Ti3O12 in Bi2O3/TiO2/SiO2/Nd2O3/Al2O3 Glass-Ceramics by Melt Quenching

A glass melt with the composition 24Bi 2 O 3 /40TiO 2 /10SiO 2 /10Nd 2 O 3 /16 Al 2 O 3 was prepared and rapidly quenched between two copper blocks (sample A). A part of this glass was subsequently crystallised at 800 °C for 8 h (sample B). For the preparation of another two samples, the melt was slowly cooled on a cooper plate (sample C) or cast into a graphite mould and subsequently thermally treated at 300 °C for 3 h (sample D). As shown by X-ray diffraction (XRD) and scanning electron microscopy (SEM) including energy dispersive X-ray spectroscopy (EDXS) and electron backscatter diffraction (EBSD) measurements, the rapidly cooled samples contained notable amounts of uncrystallised glassy phase next to the Aurivillius phase Bi 4 Ti 3 O 12 . The latter occurred in higher concentrations in all other samples and formed oriented layers. Minor concentrations of Bi 2 Al 4 O 9 and Al 2 O 3 were also detected in the microstructure.