Growing Oriented Layers of BiTiO in BiO/TiO/SiO/NdO/AlO Glass-Ceramics by Melt Quenching.

A glass melt with the composition 24BiO/40TiO/10SiO/10NdO/16 AlO 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 BiTiO. The latter occurred in higher concentrations in all other samples and formed oriented layers. Minor concentrations of BiAlO and AlO were also detected in the microstructure.