Quenched metastable phases and their transformations on heating in the Bi2O3-WO3 system

A single-roller apparatus was used to quench 16 melts in the Bi₂O₃-WO₃ system. Metastable polycrystalline phases were obtained in all compositions. Quenched specimens and their phase transformations on heating were examined by X-ray diffraction, differential thermal analysis, density measurement, electrical measurement and observation of optical anisotropy. F c c solid solutions of the type, 2WO₃ 2W ^Bi + 30 ^pI +30 _X ^PO occurred in the quenched samples for 18 to 32 mol % WO₃. Quenched phases remained unchanged with only a slight structural relaxation at temperatures lower than the first exotherm. Near the first exotherm, most samples showed an irregular change in the lattice parameter(s).