Bulk crystallization of liquid selenium Primary nucleation, growth kinetics and modes of crystallization

LÁ SZLÓ GRÁ NÁ SY, LÁ SZLÓ RÁ TKAI, ATTILA SZÁ LLÁ S, BÁ LINT KORBULY, GYULA I. TÓ TH, LÁ SZLÓ KÖ RNYEI, and TAMÁ S PUSZTAI Advances in the orientation-field-based phase-field (PF) models made in the past are reviewed. The models applied incorporate homogeneous and heterogeneous nucleation of growth centers and several mechanisms to form new grains at the perimeter of growing crystals, a phenomenon termed growth front nucleation. Examples for PF modeling of such complex polycrystalline structures are shown as impinging symmetric dendrites, polycrystalline growth forms (ranging from disordered dendrites to spherulitic patterns), and various eutectic structures, including spiraling two-phase dendrites. Simulations exploring possible control of solidification patterns in thin films via external fields, confined geometry, particle additives, scratching/piercing the films, etc. are also displayed. Advantages, problems, and possible solutions associated with quantitative PF simulations are discussed briefly.

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“…The polycrystalline structures can be formally divided into three classes (for examples, see Figure 1 [16][17][18][19][20][21][22][23][24][25] ):…”

Section: Introductionmentioning

confidence: 99%

Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites—A Review

Gránásy

Rátkai

Szàllàs

et al. 2013

Metall Mater Trans A

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“…Focusing on crystals growth rates, the values obtained from DSC data fitting (shown in Table 2) are higher compared to growth rates in pure selenium 4,40 . Thus, we can conclude that a small addition of antimony into selenium accelerates the overall crystallization process in comparison with pure selenium.…”

Section: Figurementioning

confidence: 94%

“…Appropriate prediction of crystallization process allows controlling and optimizing of conditions for new high-tech material production. Crystallization behavior can be studied directly by observing of crystals growing in material under specific conditions 4,6 or indirectly by monitoring specific properties of studied material 3,[7][8][9] . The direct observation of crystal growth is very time consuming, thus the indirect methods are preferred.…”

Section: Introductionmentioning

confidence: 99%

General Approach to the Nucleation and Crystal Growth in Sb_0.5Se_99.5 Glass Explaining the Shape of DSC Curves

Honcová

Shánělová

Barták

et al. 2016

Crystal Growth & Design

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Crystallization of amorphous Sb 0.5 Se 99.5 glass in the form of bulk and powder with defined particle sizes (prepared in protective atmosphere of argon) was studied by DSC. Different forms of sample exhibit quite complex behaviour involving crystallization on the surface and in the volume of the sample and it is reflected in the shape of DSC curve. Standard kinetic analysis cannot describe experimental results with interpretation of crystal growth mechanism, although the deconvolution procedure was done using several kinetic models, because of the time-lag of crystallization in the volume. However, theoretical curves based on nucleation and crystal growth rates, calculated separately for the process on the surface and in the volume of the sample, well correspond to real data and explain distinctive change in the shape of DSC curves with particle sizes.

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“…These crystal forms are important and ubiquitously observed in many functional materials during their processing conditions. In recent decades, the spherulitic crystal patterns are extensively studied in polymers, 4,5 liquid crystals, 5,6 proteins, 6,7 metallurgical alloys 2,3 and some biological relevance's.…”

Section: Introductionmentioning

confidence: 99%

“…This growth velocity remained constant and can be calculated by Eq. (6) for larger value of R; V = +ΔF (6) It has been concluded that, the rhythmic spherulites may have resulted by the two specific growth rates, faster growth rate followed by a slow growth rate. The growth rates were dependent in the early and late-stage nucleation.…”

mentioning

confidence: 99%

Growth Mechanism and Crystal Ordering of Spherulitic Patterns in a Belousov-Zhabotinsky Type Reaction System

Yadav¹,

Majhi²,

Srivastava³

2012

Bulletin of the Korean Chemical Society

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Three types of spherulitic morphologies have been investigated in dual substrate mode of BelousovZhabotinsky (BZ) type reaction system. Prior to growth of spherulites, three distinct patterning behaviors have been observed sequentially during the reaction process. Initial and the early-phase of reaction showed the emergence of concentric ring-like wave patterns. A colloidal-state of reaction consists of numerous fine solid particles, which forms primarily some nucleation centers of dendritic characters. The nucleation centers were found to grow in sizes and shapes with the progress of reaction. It leads to growth of dendritic-like spherulitic crystal patterns. The resultant spherulites showed transitions in their morphologies, including sea-weeds and rhythmic spherulitic crystal patterns, by the effects substituted organic substrate and in the higher concentration of bromate-initiator respectively. The branching mechanism and crystal ordering of spherulitic textures were studied with help of optical microscope (OPM) and scanning electron microscope (SEM). Characteristics of crystal phases were also evaluated using X-ray diffraction (XRD) and differential thermal analysis (DTA). Results indicated that the compositions of reactants and crystal orderings were interrelated with morphological transitions of spherulites as illustrated and described.

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Bulk crystallization of liquid selenium Primary nucleation, growth kinetics and modes of crystallization

Cited by 88 publications

References 29 publications

Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites—A Review

Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites—A Review

General Approach to the Nucleation and Crystal Growth in Sb_0.5Se_99.5 Glass Explaining the Shape of DSC Curves

Growth Mechanism and Crystal Ordering of Spherulitic Patterns in a Belousov-Zhabotinsky Type Reaction System

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Bulk crystallization of liquid selenium Primary nucleation, growth kinetics and modes of crystallization

Cited by 88 publications

References 29 publications

Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites—A Review

Phase-Field Modeling of Polycrystalline Solidification: From Needle Crystals to Spherulites—A Review

General Approach to the Nucleation and Crystal Growth in Sb0.5Se99.5 Glass Explaining the Shape of DSC Curves

Growth Mechanism and Crystal Ordering of Spherulitic Patterns in a Belousov-Zhabotinsky Type Reaction System

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Product

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General Approach to the Nucleation and Crystal Growth in Sb_0.5Se_99.5 Glass Explaining the Shape of DSC Curves