Crystal nucleation in silicate glasses: the temperature and size dependence of crystal/liquid surface energy

Fokin, Vladimir M.; Zanotto, Edgar Dutra

doi:10.1016/s0022-3093(99)00877-7

Cited by 99 publications

(102 citation statements)

References 18 publications

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“…1 shape of the pore walls and at the sphere shape at the bottom of the pore. The surface energy decreases with decreasing the surface radius of curvature, especially in the nanometer scale as in our case, leading to an increase of the liquid solute concentration adjacent to the curved surface [17][18][19]. The maximum concentration of the solute ions in the liquid solution is expected to be at the bottom of the pore site where the local surface radius of curvature is the smallest compared to all sites of the pore walls surface, as seen in Fig.…”

Section: Resultssupporting

confidence: 54%

Highly Sensitive Piezoelectric Response of Sodium Nitrite Nano-crystals to Low Applied Mechanical Pressures

Bishara¹,

Berger²

2018

JMSE-A

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Development of highly-sensitive detectors of low mechanical pressures in the scale of few Pascal and below in environmental conditions are of a high technological demand for a variety of applications such as a remote control of infants breathing and a leakage alert of hazardous gases. This paper reports on a highly sensitive piezoelectric detector of low applied mechanical pressures down to 0.1 Pa in atmospheric environment (10 -4 % pressure change). It is made of SN (sodium nitride) nanocrystals grown inside alumina pores with a preferred crystallographic orientation that can be controlled by their formation conditions based on a thermodynamic driving force. The SN nanocrystals inside the pores show a piezoelectric current response to low applied mechanical pressure which depends on the crystallographic orientation of the crystals and the level of residual or applied static strains. The piezoelectric current response is correlated with the unique molecular structure of the SN crystals.

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Section: Resultssupporting

confidence: 54%

Highly Sensitive Piezoelectric Response of Sodium Nitrite Nano-crystals to Low Applied Mechanical Pressures

Bishara¹,

Berger²

2018

JMSE-A

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“…However, simulations carried out by Fokin and Zanotto 11 for a model glass demonstrated that W* is weakly affected by ρ(R).…”

Section: Resultsmentioning

confidence: 97%

“…The same values of δ used by Fokin & Zanotto 11 were also used here to evaluate σ cl (R, T) through the decoupling equations for the silicate glasses investigated.…”

Section: Calculationsmentioning

confidence: 99%

“…Several assumptions have been investigated to explain the reasons for these discrepancies: i) metastable phase formation [7][8] ; ii) the influence of H 2 O content on crystal nucleation rates 9 ; iii) the possible breakdown of the Stokes-Einstein equation at (∆T/T m ~ 0.5-0.6), which must not be applied to express the crystal nucleation kinetic as governed by viscous flow 10 ; and iv) the absence of an experimental technique to accurately determine the surface energy of nanometric aggregates independently of nucleation experiments 11 . Based on the latter assumption, the CNT assumes that surface energy is a macroscopic thermodynamic property with a value equal to that of a planar interface, σ ∞ .…”

Section: Introductionmentioning

confidence: 99%

“…In addition, there is some experimental evidence that crystal-melt surface energy should decrease with increasing temperature 11 . According to several researchers [16][17] , a plot of σ cl (T) may indicate a size effect, because the surface energy σ cl (T, R) calculated from nucleation data refers to nuclei of critical size, R*.…”

Section: Introductionmentioning

confidence: 99%

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Effect of different approaches to decouple the dependence of nuclei-liquid surface energy on size and temperature

et al. 2009

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Tests involving the Classical Nucleation Theory (CNT) often disregard the size dependence of surface energy. Thus, the surface energy of critical nuclei is assumed to be a macroscopic quantity that depends only on the temperature of a flat surface. However, because the size of critical nuclei changes with temperature, σ cl (T) should be described as a function of both temperature and size of critical nuclei. The present work examines the temperature dependence of macroscopic surface energy, decoupling it from the size dependent part. Tolman, Rasmussen and Vogelsberger's equations are used to decouple the dependence of surface energy on size, using experimental data for the following silicate glasses Li 2 O.2SiO 2 (LS 2 ) and Na 2 O.2CaO.3SiO 2 (N 1 C 2 S 3 ). These equations are successful in obtaining a decrease in σ cl (T), in agreement with theoretical predictions. For all the values of δ, Tolman's equation produces the lowest values of σ cl (T). Nevertheless, they are very close to the liquid/ vapor surface energy (σ lv ), which contradicts the Stefan's rule (i.e. σ cl /σ lv << 1). Therefore, it is demonstrated that the assumption of the curvature dependence of surface energy does not suffice, per se, to explain the discrepancy between the experimental and theoretical values of nucleation rates.

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Nucleation and Crystallization Kinetics in Silicate Glasses: Theory and Experiment

Fokin

Yuritsyn

Zanotto

2005

Nucleation Theory and Applications

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All truths are easy to understand once they are discovered; the point is to discover them. Galileo GalileiExperimental data on internal homogeneous crystal nucleation in silicate glasses obtained in the last four decades are analyzed in detail in the framework of the classical nucleation theory (CNT). Despite the fact that reasonable qualitative interpretations of the temperature and time dependences of nucleation rates are given by CNT, it meets with serious problems in their quantitative description. Different reasons for this failure are tested and discussed. The main conclusion is that, in contrast to Gibbs' description of heterogeneous systems, the thermodynamic properties of critical nuclei which, to a large extent, govern nucleation kinetics, generally differ from those of the corresponding macrophase. A number of evidences based on the analysis of both crystal nucleation and growth data are given for a decreased thermodynamic driving force for crystallization and critical nuclei/liquid interfacial energy, as compared with the respective properties of the macro-phase. Special attention is devoted to the widespread and practically important type of heterogeneous nucleation -nucleation on glass surfaces. A comparative analysis of available data on surface and bulk nucleation rate data is performed. IntroductionGlasses can be defined as noncrystalline solids that, in the course of their preparation, undergo a process commonly denoted as glass transition. One of the most important (but not the only) ways of vitrification consists in supercooling a liquid suppressing crystallization. When a liquid is cooled down with sufficiently high rates, crystallization may occur to a very limited degree or be completely absent down to temperatures corresponding to very high viscosities in the range η ≥ 10 13 -10 12 Pa · s ∼ = η(T g ), where T g is defined as the glass transition temperature. Below this temperature, the viscosity is so high that large-scale atomic rearrangements in the system are no longer possible within the time-scale of the experiment, and the structure freezes-in, i.e., the structural rearrangements required to retain the liquid in the appropriate metastable equilibrium state cannot follow any more the changes of temperature. This process of freezing-in of the structure of an undercooled liquid is commonly denoted as glass transition and, as a result, the system is transformed into a glass. Typical glass-forming liquids, such as silicate melts, are commonly characterized by: (i) relatively high viscosities (η > 100 Pa · s) at the melting point (or liquidus), and (ii) a steep increase of the viscosity with decreasing temperature. These properties favor the process of transformation of a liquid into a glass. The above mechanism discussed leads to the conclusion that the glass structure is very similar to that of the parent (undercooled) liquid at temperatures near T g .

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Crystal nucleation in silicate glasses: the temperature and size dependence of crystal/liquid surface energy

Cited by 99 publications

References 18 publications

Highly Sensitive Piezoelectric Response of Sodium Nitrite Nano-crystals to Low Applied Mechanical Pressures

Highly Sensitive Piezoelectric Response of Sodium Nitrite Nano-crystals to Low Applied Mechanical Pressures

Effect of different approaches to decouple the dependence of nuclei-liquid surface energy on size and temperature

Nucleation and Crystallization Kinetics in Silicate Glasses: Theory and Experiment

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