Local ordering and interfacial structure between spinel crystal and aluminosilicate glasses from molecular dynamics simulations

Abstract

Molecular dynamics simulations were performed to investigate the interfaces of soda magnesia aluminosilicate glass and MgAl2O4 spinel crystals. The glass structures were first generated and characterized. It was found that the glass‐forming network consists of fourfold coordinated [SiO4] and [AlO4] tetrahedra connected through corner sharing with Na+ and Ca2+ acting as modifiers or charge compensators. The glass and crystal interfaces were then constructed on low energy spinel surfaces with special measures to ensure two natural interfaces. The interfacial structures were characterized by z‐density profile, pair distribution function and coordination number analysis. The results show that there exist local ordering on the glass side and preferential adsorption of specific cation near the interface. Cation coordination analyses showed that aluminum ions changed from mainly fourfold coordination in the glass to five and sixfold coordination near the interface suggesting a gradual change in structural role of aluminum from the glass to the crystal. The ordering and segregation of cations, as well as change in aluminum coordination, at the glass/crystal interface strongly suggest that the ordered crystal structure influence the atom distribution and local structure of the adjacent glasses and this ordering can be the initial stage of nucleation or crystal growth.

Effects of Surface Orientation and Termination Plane on Glass‐to‐Crystal Transformation of Lithium Disilicate by Molecular Dynamics Simulations

“…As the crystal part is fixed in this study, the interface area consists of the terminated layer from crystal side and few angstroms of surface region within the glass region, which is generated and considered as glass bulk due to the periodic boundary condition. [27,28] As expected, the crystal surface terminations impact atomic reorganization in glass that comes directly in their contact. In Figure 5b, the two terminations of LS2(110) result in different z-density profiles for the two interface regions.…”

“…[ 25 ] Rushton et al [ 26 ] showed distinct atomic density profiles of interfaces between sodium lithium borosilicate and different MgO/CaO crystal surfaces. Sun and Du [ 27 ] reported that in the MD simulated MgAl 2 O 4 /aluminoborosilicate glass [ 27 ] interface, a highly ordered [SiO 4 ] tetrahedron layer forms near Al‐terminated MgAl 2 O 4 crystal.…”

“…In the early studies mentioned earlier, this distinction was based on the atomic density profiles along the interface normal. Recently, Sun and Du [27,28] reported the structures of interfacial region between aluminoborosilicate glass and MgAl 2 O 4 spinel crystals using the recently developed classic interatomic potentials. [29] The results show that the coordination number changes, and the bond distance between O and Al/B atoms can be a useful indicator of crystallization of glass owing to the distinct Dr. W. Sun, Prof. V. Dierolf, Prof. H. Jain Institute for Functional Materials and Devices Lehigh University Bethlehem, PA 18015, USA E-mail: h.jain@lehigh.edu…”

Interfacial structures of spinel crystals with borosilicate nuclear waste glasses from molecular dynamics simulations

“…Rushton et al reported interfaces between sodium lithium borosilicate glasses and the MgO and CaO crystals and found that the borate and silicate polyhedral shows strong correlation on position and orientation . We have recently reported the interfacial behaviors between soda magnesia aluminosilicate glass and MgAl 2 O 4 spinel crystals and found that that aluminum ions changed from mainly fourfold coordination in the glass to five and sixfold coordination near the interface . This provides evidence of the influence of the crystal structure on that of the glass at the interface, which can be an initial stage of crystal growth.…”

Molecular dynamics investigation of the fracture mechanism of a glass‐ceramic containing cleavable crystals

“…Although the accessible time and length scales are limited, MD simulations have been successfully applied to investigate glass/ceramics interfaces and their composites. For example, Galiolini et al have devoted to understand adhesion between an oxide glass and Al 2 O 3 and Si 3 N 4 , Sun and Du have recently investigated an interlayer between an aluminosilicate glass and a MgAl 2 O 4 spinel crystal, and Lusvardi et al have tried to evaluate possibility of crystallization in some oxide glasses. Furthermore, fracture patterns in amorphous aluminum nano‐particles embedded soda‐lime silica glass have been investigated .…”