Browsing by Author "Milanova M."

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    Glass formation and structure of glasses in the ZnO-WO3-La2O3-Al2O3 system
    (2015-01-01) Ataalla M.; Milanova M.; Aleksandrov L.; Iordanova R.; Staneva A.; Dimitriev Y.
    The glass formation region in the section 90(xZnO.yWO3.zLa2O3).10Al2O3 of a constant Al2O3 content of 10 mol % and varying amounts of WO3, ZnO and Nd2O3 from ZnO-WO3-La2O3-Al2O3 system is determined by the melt quenching technique (with cooling rates of 10 Ks-1 - 102 Ks-1). The glasses are obtained from compositions of a high WO3 content (60 mol % - 75 mol %). The amorphous state of the samples is verified by X-ray diffraction (XRD). The thermal parameters of the investigated glasses are obtained by differential thermal analysis (DTA). The glass transition temperature (Tx) is in the range 440°C - 510°C, while the crystallization temperature (Tg) varies from 520°C to 650°C. The glasses are characterized by a good thermal stability in respect to crystallization. ΔT varies in the range of 60°C - 135°C (ΔT = Tx-Tg). The glasses structure is studied by IR spectroscopy. It is established that the amorphous network is built up mainly by WO6 octahedra connected through W-O-W bridges.