Structure of Glasses and Melts

Wilding, Martin C.; Benmore, C. J.

doi:10.2138/rmg.2006.63.12

Cited by 31 publications

(22 citation statements)

References 147 publications

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“…Silica (SiO 2 ) and its mixtures with other oxides (such as Na 2 O, K 2 O, Y 2 O 3 , MgO, CaO, Al 2 O 3 , and PbO 2 ) play a significant role in many geochemical and geophysical phenomena [1][2][3][4][5]. These oxides are important materials in the glass and ceramics industry.…”

Section: Introductionmentioning

confidence: 99%

Coordination and polyamorphism of aluminium silicate under high pressure: insight from analysis and visualization of molecular dynamics data

et al. 2014

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The amorphous aluminium silicate (Al 2 O 3 )·2(SiO 2 ) (abbreviated as AS2) is investigated using a molecular dynamics simulation with the Born-Mayer potential. The models of amorphous AS2 are constructed in a wide pressure range. The results show that the structure of AS2 mainly consists of the basic structural units TO x (T is Al or Si; x = 4, 5, 6). The topology of basic structural units at different pressures is identical. Two adjacent units TO x are linked to each other through common oxygen atoms and form a continuous random network of basic structural units TO x . The different aluminium silicate states result from the difference of the fraction of units TO x and their spatial distributions. The coordination units (triclusters) OAl 3 and OSi 3 and (tetraclusters) OAl 4 and OSi 4 result in AlO x -rich and SiO x -rich regions, and this is the origin of the microphase separation. Regarding the polymorphism, it can be seen that the structure of AS2 comprises three structural phases: TO 4 , TO 5 , and TO 6 structural phases. The size of TO 4 structural phase regions decreases and the size of TO 6 structural phase regions increases as pressure increases. Inversely, the size of TO 5 structural phase regions increases to a maximum value and then decreases as pressure increases. In the considered pressure range, with increasing pressure, there is a transformation from TO 4 structural phase (at low pressure) to TO 6 structural phase (at high pressure). PACS Nos.: 61.43.Bn, 61.43.Fs. Résumé : Nous étudions le silicate d'aluminium amorphe (Al2O3)·2(SiO2) (abréviation AS2), en utilisant une simulation de dynamique moléculaire avec le potentiel de Born-Mayer. La modélisation est faite pour un large domaine de pression. Les résultats indiquent que la structure du AS2 est principalement constituée des unités structurelle de base TO x (T est Al ou Si et x = 4, 5, 6). La topologie des unités structurelles de base aux différentes pressions est identique. Deux unités adjacente de TO x sont liées ensemble via des atomes d'oxygène communs et forment un réseau aléatoire d'unités structurelles de base TO x . Les différents états du silicate d'aluminium résultent de la différence des fractions d'unités TO x et de leur distribution spatiale. Les unités de coordination triple amas OAl 3 , OSi 3 et quadruple amas OAl 4 , OSi 4 résultent en régions riches en AlO x et SiO x et ceci est à l'origine de la séparation en micro-phases.En ce qui concerne le polymorphisme, on constate que la structure de AS2 comprend trois phases structurelles : TO 4 , TO 5 et TO 6 . Lorsque la pression augmente, la grandeur des régions de phase structurelle TO 4 décroit, alors que la grandeur des régions TO 6 augmente. Inversement, la grandeur des régions de phase structurelle TO 5 augmente d'abord avec la pression jusqu'à un maximum, pour diminuer ensuite si la pression continue d'augmenter. Dans le domaine de pression considéré ici, il y a une transformation de la phase structurelle TO 4 (à basse pression) vers la phase structurelle TO 6 (à haute pression)...

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Section: Introductionmentioning

confidence: 99%

Coordination and polyamorphism of aluminium silicate under high pressure: insight from analysis and visualization of molecular dynamics data

et al. 2014

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“…Recent advances in synchrotron X-ray and neutron scattering combined with techniques for data analysis are revolutionising structural studies of amorphous systems under high pressure, high temperature, and combined high-P,T conditions [104,106,107]. Information on the structure factor (S(Q)) and inter-atomic pair potentials derived from these studies are critical for developing and testing models for structural relaxation occurring in the melts and glasses at high pressure, and modeling the entropy, rheology and glass transition behavior.…”

Section: General Considerationsmentioning

confidence: 99%

“…Information on the structure factor (S(Q)) and inter-atomic pair potentials derived from these studies are critical for developing and testing models for structural relaxation occurring in the melts and glasses at high pressure, and modeling the entropy, rheology and glass transition behavior. In particular, the in situ high-P studies are providing valuable new insights into liquid and glassy polyamorphism, and for deciphering the coordination chemistry of ions like Mg 2+ in silicate systems, that play an intermediate role between network-former and structure-modifying cations [107][108][109][110][111][112][113][114][115]. It is not yet clear how their coordination changes affect the rheology at high pressure.…”

Section: General Considerationsmentioning

confidence: 99%

“…High pressure studies of liquid and amorphous structure are particularly important for studying and identifying systems that may contain liquid-liquid or polyamorphic transitions. However, the scattered signals from amorphous solids and liquids are weak and broad and great care must be taken in properly subtracting background scattering from the high pressure sample environment in order to extract and interpret the data [107,115,116].…”

Section: General Considerationsmentioning

confidence: 99%

“…Although these apparatus are not transparent to visible, IR or UV radiation, the sample and pressurization environments can be designed so that X-ray beams can penetrate the sample chamber and the scattered radiation be detected over a wide angular range [107]. In addition, the sample containers and pressurization assemblies can be made from materials that are relatively transparent to incident and scattered neutron beams [112].…”

Section: General Considerationsmentioning

confidence: 99%

See 2 more Smart Citations

High pressure effects on liquid viscosity and glass transition behaviour, polyamorphic phase transitions and structural properties of glasses and liquids

McMillan

Wilding

2009

Journal of Non-Crystalline Solids

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Structure and Properties of Nanoglasses

et al. 2018

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Nanoglasses represent a novel structural modification of amorphous materials, exhibiting properties and structural details that are markedly different from those observed in metallic glasses prepared by rapid quenching. In this review, the synthesis method and the techniques used for charactering the structure of nanoglasses are described together with our current understanding of their salient microstructural features. It is believed that the structure of nanoglasses consists of two distinct amorphous regions give rise to mechanical, thermal, and magnetic properties that are significantly different from those observed in rapidly quenched (RQ) metallic glasses. Nanoglasses, therefore, constitute a distinct new class of amorphous materials and thus opening up new opportunities for their potential use in a number of structural and functional applications.

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Structure of Glasses and Melts

Cited by 31 publications

References 147 publications

Coordination and polyamorphism of aluminium silicate under high pressure: insight from analysis and visualization of molecular dynamics data

Coordination and polyamorphism of aluminium silicate under high pressure: insight from analysis and visualization of molecular dynamics data

High pressure effects on liquid viscosity and glass transition behaviour, polyamorphic phase transitions and structural properties of glasses and liquids

Structure and Properties of Nanoglasses

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