Molecular phase separation effects on calorimetric properties GexSe80-xPb20 Glasses

Kumar, Kamal and Purohit, L.P. and Mehra, R.M. and Deep, Akash (2011) Molecular phase separation effects on calorimetric properties GexSe80-xPb20 Glasses. Chalcogenide Letters, 8 (11). pp. 659-670. ISSN 1584-8663

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Abstract

The influence of molecular phase separation on thermal activation barriers of phase transformations in GexSe80-xPb20 glasses has been investigated using non-isothermal methods. Kinetic parameters of glass transition, crystallization and decomposition were determined using differential scanning calorimetric and thermo-gravimetric measurements. The model free Kissinger and isoconversional Flynn-Wall-Ozawa methods were employed to calculate the activation energies of thermally induced structural transitions. The observed variation in thermal properties with Ge content in place of Se could be interpreted in terms of the formation of tetrahedrally coordinated Ge-Se structural units at expense of Se-Se units. Deviations in the activation energies of crystallization and decomposition with the extent of conversion indicate the mechanistic complexity of the transformations as these involve different nucleation and growth events due to the presence of different phases. GexSe80-xPb20 glass with x  20 has been found to attain the maximum activation barriers showing high thermal stability and structural rigidity.

Item Type: Article
Uncontrolled Keywords: Chalcogenides, Calorimetry, Isoconversional Models, Phase Separation
Subjects: CSIO > Materials Science
Depositing User: Ms. J Shrivastav
Date Deposited: 21 Apr 2012 22:44
Last Modified: 21 Apr 2012 22:44
URI: http://csioir.csio.res.in/id/eprint/261

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