Crystal growth and viscous flow in barium disilicate glass

Rodrigues, Alisson Mendes; Cassar, Daniel R.; Fokin, Vladimir M.; Zanotto, Edgar Dutra

doi:10.1016/j.jnoncrysol.2017.10.007

Cited by 37 publications

(39 citation statements)

References 23 publications

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“…However, it has been shown that the Stokes‐Einstein equation breaks down above the glass transition temperature . The breakdown for BaO∙2SiO 2 occurs near 1140K (1.18

T_{g}

) which is approximately equal to the DTA crystallization peak maximum temperature (see Figure and Figure respectively). Here we show additional evidence of this breakdown in the DTA results.…”

Section: Numerical Modelmentioning

confidence: 97%

Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass

et al. 2020

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The accuracy of a differential thermal analysis (DTA) technique for predicting the temperature range of significant nucleation is examined in a BaO•2SiO 2 glass by iterative numerical calculations. The numerical model takes account of time-dependent nucleation, finite particle size, size-dependent crystal growth rates, and surface crystallization. The calculations were made using the classical and, for the first time, the diffuse interface theories of nucleation. The results of the calculations are in agreement with experimental measurements, demonstrating the validity of the DTA technique. They show that this is independent of the DTA scan rate used and that surface crystallization has a negligible effect for the glass particle sizes studied. A breakdown of the Stokes-Einstein relation between viscosity and the diffusion coefficient is demonstrated for low temperatures, near the maximum nucleation rate. However, it is shown that accurate values for the diffusion coefficient can be obtained from the induction time for nucleation and the growth velocity in this temperature range. K E Y W O R D Sbarium silicate glasses, differential scanning calorimetry, differential thermal analysis, nucleation, simulation 2472 |

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“…However, it has been shown that the Stokes‐Einstein equation breaks down above the glass transition temperature . The breakdown for BaO∙2SiO 2 occurs near 1140K (1.18

T_{g}

) which is approximately equal to the DTA crystallization peak maximum temperature (see Figure and Figure respectively). Here we show additional evidence of this breakdown in the DTA results.…”

Section: Numerical Modelmentioning

confidence: 97%

Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass

et al. 2020

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“…This 60 minutes delay is observed in the behavior of all other Raman peaks and suggests that no structural changes are revealed within the Raman spectra during this time. An induction time of 35 minutes is expected for crystallization at 790°C based on the experimentally available data …”

Section: Resultsmentioning

confidence: 99%

“…Cubic specimens of uniform thickness (2.0 × 2.0 × 1.5 mm), devoid of bubbles were chosen for this high‐temperature experiment. Using a heating rate of 10 K/min, differential scanning calorimetry (DSC) results show that the glass transition temperature (T g ) and the two crystallization peaks of this glass which reveal them to be 690°C, 853°C, and 905°C, respectively . One sample was heated at a rate of 25°C/min from 25°C up to 790°C (±5°C) and held constant for 440 minutes during the experiment.…”

Section: Methodsmentioning

confidence: 99%

“…One sample was heated at a rate of 25°C/min from 25°C up to 790°C (±5°C) and held constant for 440 minutes during the experiment. At this temperature for BS2 glass, the crystallized fraction is mostly a consequence of the growth of pre‐existing crystals (which formed during the quenching and heating procedures) in the volume . By applying the Avrami equation to existing experimental nucleation and growth rate data we calculate that after 440 minutes at 790°C the volume fraction crystallized is 99%.…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, the surface layer of crystals is only 3 μm in thickness after 440 minutes. We refer the reader to Figure B of reference to view an example of surface and internal crystallization in BS2 glass. In this study, the sample overwhelmingly crystallizes from within the SCL volume rather than the surface.…”

Section: Methodsmentioning

confidence: 99%

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A Raman investigation of the structural evolution of supercooled liquid barium disilicate during crystallization

Moulton

Rodrigues

Pizani

et al. 2018

Int J of Appl Glass Sci

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The homogeneous and stoichiometric crystallization of the barium disilicate (BaSi2O5) glass makes it possible to follow the structural evolution of Raman bands from the supercooled liquid to the crystalline phase. We monitored the crystallization of supercooled liquid BaSi2O5 at 790°C over 440 minutes revealing a three‐stage crystallization process: stage 1 involves changes in the barium sites toward a bonding environment that is similar to that in orthorhombic low barium disilicate. The end of stage 1 is marked by the loss of the Q4 species vibration at 1170 cm−1 and the creation of a crystalline band at 490 cm−1. Stage 2 is marked by the transition of the Q3 peak (1060 cm−1) from a Gaussian‐like to a Lorentzian curve, indicating the formation of well‐developed sheet structures. These observations lead us to conclude that the Raman spectra are resolving both the crystalline L‐BS2 phase and the BS2 melt. The final stage involves a rapid decrease in the remaining Qn species to form Q3. This crystallization process involves structural modifications that occur on the tens of microns scale. The barium cations drive the initial stages of crystallization, providing direct evidence that the short‐range order, around network modifiers, is a critical factor involved in homogeneous crystallization.

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Glass‐Ceramic Technology

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Crystal growth and viscous flow in barium disilicate glass

Cited by 37 publications

References 23 publications

Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass

Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass

A Raman investigation of the structural evolution of supercooled liquid barium disilicate during crystallization

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Crystal growth and viscous flow in barium disilicate glass

Cited by 37 publications

References 23 publications

Modeling nonisothermal crystallization in a BaO∙2SiO2 glass

Modeling nonisothermal crystallization in a BaO∙2SiO2 glass

A Raman investigation of the structural evolution of supercooled liquid barium disilicate during crystallization

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Contact Info

Product

Resources

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Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass

Modeling nonisothermal crystallization in a BaO∙2SiO₂ glass