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Structural and electrical studies of tungsten based glass-ceramics

Glass-ceramics based on 5M2O-5ZnO-40P2O5-50WO3 (in mol%, M = Li, Na, Ag) glasses were prepared by heat- treatment of the samples in the form of bulk and powder pellets at 725 and 800 ˚C for 6 hours. Structure and morphology of prepared glass-ceramics were studied by powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), while electrical properties were investigated using impedance spectroscopy. PXRD diffractograms show that two polymorphs of W2O3(PO4)2, rhombic and monoclinic, formed during crystallization in bulk samples prepared at 725 and 800 ˚C and pelleted samples prepared at 725 ˚C. However, diffractograms of pelleted samples heated at 800 ˚C show a distinct lack of diffraction peaks of rhombic polymorph. Furthermore, SEM and EDS have confirmed that the degree of crystallization increases with increasing temperature. Values of DC conductivity of measured glass-ceramics are similar to their parent glasses. This result indicates that crystallization does not impede polaronic transport in these glass-ceramics, thus producing conductive and hardy materials.

Impendance spectroscopy ; Glass-ceramics ; Electrical properties

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