R K MISHRA
Articles written in Bulletin of Materials Science
Volume 19 Issue 2 April 1996 pp 357-371
The Gibbs free energy difference (Δ
Volume 19 Issue 4 August 1996 pp 699-711
The temperature dependence of the viscosity of the undercooled melts exhibits an important role in the study of nucleation, crystal growth and the glass-forming ability of materials. Several attempts have been made to study the viscous behaviour of the glass-forming melts and these investigations are mainly based on free volume theory as well as on the configurational entropy model. In the present investigation, an attempt has been made to correlate the thermodynamic parameters with the viscosity of the glass-forming melts and to study the temperature dependence of the viscosity of undercooled liquids on the basis of the free volume theory as well as on the basis of the configurational entropy model of Adam and Gibbs. The entire study is confined on the expression for thermodynamic parameters reported by the authors recently. The expression obtained has been successfully applied to study the temperature dependence of the viscosity of the metallic, molecular and oxide glass-forming liquids.
Volume 42 Issue 5 October 2019 Article ID 0211
Pellet leaching and associated thermal and structural changes of sodium borosilicate (NBS) glass, used for the immobilization of high-level radioactive liquid waste, subjected to aggressive test conditions have been compared with international simple glass (ISG) subjected to the same leaching conditions. The crystalline phase getting separated out from NBS glass is found to be different for pellets and powder leaching experiments and this has been explained based on the difference in the extent of leaching occurring with glass samples in the two experiments. Based on Fourier transform infrared studies, it is inferred that, unlike in the ISG sample, Si–O–Si/B structural units become more ordered with the leaching in the case of NBS glass, and this is attributed to the partial network destruction occurring with NBS glass and crystallization of the SiO₂ phase from the glass matrix. Both the NBS glass and ISG sample show L-centre emission and the emission intensity remained unaffected with leaching, conﬁrming that the local environment around non-bridging oxygen atoms in the NBS glass and ISG sample are unaffected and leaching occurs through network dissolution.
Volume 43, 2020
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