Murugan, Senthil G and Varma, KBR (1999) Structural, dielectric and optical properties of lithium borate-bismuth tungstate glass-ceramicsc. In: Materials Research Bulletin, 34 (14-15). pp. 2201-2213.
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Glasses in the system (1 - x)Li2B4O7-xBi(2)WO(6) (0.1 less than or equal to x less than or equal to 0.35) were prepared by splat quenching technique. Powder X-ray diffraction (XRD) and differential thermal analysis (DTA) were employed to characterize the as-quenched glasses. High-resolution transmission electron microscopy (HR TEM) revealed the presence of fine, nearly spherical crystallites of Bi2WO6 varying from 1.5 to 20 nm in size, depending on x in the as-quenched glasses. The glasses (corresponding to x = 0.3) heat-treated at 723 K for 6 h gave rise to a clear crystalline phase of Bi2WO6 embedded in the Li2B4O7 glass matrix, as observed by X-ray studies. The dielectric constants of the as-quenched glasses as well as the glass-ceramics decreased with increase in frequency (40Hz-100 kHz) at 300 K, and the value obtained for the glass-ceramic (x = 0.2) is in agreement with the values predicted using Maxwell's model and the logarithmic mixture rule. The dielectric constants for both the as-quenched glass and the glass-ceramic increased with increase in temperature (300 - 873 K) and exhibited anomalies close to the onset of the crystallization temperature of the host glass matrix. The optical transmission properties:of these glass-ceramics were found to be compositional dependant. (C) 2000 Elsevier Science Ltd.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science.|
|Keywords:||A.ceramics;A.glasses;C.electron microscopy;C.X-ray diffraction;D.dielectric properties|
|Department/Centre:||Division of Chemical Sciences > Materials Research Centre|
|Date Deposited:||30 Jun 2011 07:51|
|Last Modified:||30 Jun 2011 07:51|
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