Surface-induced devitrification of glasses: the influence of elastic strains

Schmelzer, Jürn W. P.; Pascova, R.; Möller, Jörg; Gutzow, I.

doi:10.1016/0022-3093(93)90738-j

Cited by 91 publications

(53 citation statements)

References 20 publications

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“…e.g. [3,4]). The compositions of the studied glass, before and after re-melting, are shown in Table 8.1.…”

Section: Methodsmentioning

confidence: 99%

“…The melting procedure, the experimental results for the glass compositions, obtained by XFR-analysis, and the experimental conditions, realized to prepare the different glass fractions, are reported in previous papers. "Green" samples with initial size 10/10/(8-10) mm 3 were prepared by mixing the parent glass powders with 7.5 % PVA solution and by un-axial pressing at 100-150 MPa. After drying and a 30 min holding at 270 ∘ C (to eliminate the PVA) the samples were heated to different temperatures in the range 650-1000 ∘ C at a heating rate of 5 ∘ C/min and then sinter-crystallized for 1-10 hours.…”

Section: Methodsmentioning

confidence: 99%

“…In the case of diopside, it was assumed that ρ cr and ρ g(cr) have values of 3.27 and 2.75 g/cm 3 , respectively. The experimental associated error of the ρ g and ρ gc values was evaluated as ± 0.003 g/cm 3 , which corresponds to an experimental error of ±1 % on the evaluation of the amount of the formed diopside. A detailed description of the methodological approach is given in [67].…”

Section: Methodsmentioning

confidence: 99%

“…Firstly, skeleton density was measured and then the absolute density after crashing and milling the samples below 26 μm. The experimental associated errors to the evaluation of ρ a , ρ gc and ρ s were estimated as ±0.013 g/cm 3 , ±0.003 g/cm 3 and ±0.005 g/cm 3 , respectively. The experimental error associated to P T and P C was evaluated as ±0.6 % and ±0.3 %, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…These stresses may strongly affect the kinetics of phase transitions in condensed sys-tems [1]. In more detail, the influence of internal elastic stresses on crystal nucleation and growth rates in glasses is considered from both theoretical and experimental points of view, for example, in [2][3][4][5][6][7]. A detailed overview on different investigations on the effect of elastic stresses on segregation and crystallization processes in glassforming melts is given in [8].…”

Section: Introductionmentioning

confidence: 99%

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8. Stress-induced Pore Formation and Phase Selection in a Crystallizing Stretched Glass

Fokin¹,

Karamanov²,

Abyzov³

et al. 2014

Glass

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In the present chapter, we describe results of experimental investigations and theoretical analysis of phase selection and nucleation of pores in small samples of undercooled diopside liquid when it is enclosed by a solid crystalline surface layer. The formation of the surface crystalline layer starts with nucleation and growth of highly dense diopside crystals. At the moment of impingement of these crystals on the sample surface, the crystallization pathway switches from diopside to a wollastonite-like (WL) phase. The origin of such switch can be explained by the fact that the formation of the WL-crystal produces less elastic stress energy than the same amount of diopside. This difference is due to the lower (as compared to diopside) density of the WL-crystal phase, which is closer to the liquid density. The relative content of the two crystalline phases can be changed by varying the sample size. Due to the density misfit the growth of the WL-crystalline layer leads to uniform stretching of the encapsulated liquid. This negative pressure leads finally to the formation of one small pore, which rapidly grows up to a size that almost eliminates the elastic stress and, therefore, dramatically reduces the driving force for further pore nucleation. The nucleation process of the pore is experimentally found to occur in a very narrow range of the relative widths of the surface layer (compared to the sample size) and, consequently, of negative pressures. We consider this fact as an indication that pore nucleation proceeds via homogeneous nucleation. The above-given qualitative explanation of the observed phenomena is corroborated by detailed theoretical calculations of elastic stress fields and their impact on phase selection and pore nucleation. Good qualitative and partly even quantitative agreement between experiment and theory is found. An overview on other systems with similar or related properties is included as well. The findings of this research are quite general because the densities of most glasses significantly differ from those of their iso-chemical crystals. By this reason, the studied phenomena are of high technological significance for the development of different types of glass-ceramic materials and the understanding and control of sinter-crystallization processes. The latter problem is also considered in the present chapter.

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“…e.g. [3,4]). The compositions of the studied glass, before and after re-melting, are shown in Table 8.1.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

8. Stress-induced Pore Formation and Phase Selection in a Crystallizing Stretched Glass

Fokin¹,

Karamanov²,

Abyzov³

et al. 2014

Glass

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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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Viscous‐Phase Silicate Processing

Müller¹,

Reinsch²

2012

Ceramics and Composites Processing Methods

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Surface-induced devitrification of glasses: the influence of elastic strains

Cited by 91 publications

References 20 publications

8. Stress-induced Pore Formation and Phase Selection in a Crystallizing Stretched Glass

8. Stress-induced Pore Formation and Phase Selection in a Crystallizing Stretched Glass

Nucleation and Crystallization Kinetics in Silicate Glasses: Theory and Experiment

Viscous‐Phase Silicate Processing

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