Structural and dynamic properties of aluminosilicate melts: a molecular dynamics study

Area of Science:

• Materials Science
• Computational Chemistry
• Geophysics

Background:

• Aluminosilicates (AS) are crucial in materials science and geology.
• Understanding their structural and dynamic properties is key for applications.
• Previous models lacked comprehensive accuracy across compositions.

Purpose of the Study:

• To investigate the structural and dynamic properties of aluminosilicates (AS) across varying Al2O3 concentrations.
• To validate a Born-Mayer-Huggins potential for AS melts.
• To correlate melt properties with local structural changes.

Main Methods:

• Molecular dynamics (MD) simulations were employed.
• A transferable Born-Mayer-Huggins potential was assessed for AS.
• Structural properties (X-ray structure factor, pair-correlation functions, coordination numbers) and dynamic properties (viscosity, self-diffusion) were calculated.

Main Results:

• The chosen potential accurately reproduces experimental data for AS melts.
• Viscosity increases with temperature, and fragility increases with Al2O3 content.
• Increased Al2O3 content correlates with changes in triply bonded oxygen (TBO), AlO5, and AlO6 structural units.

Conclusions:

• The validated potential is reliable for simulating AS melts.
• Al2O3 concentration significantly influences AS melt dynamics and structure.
• Fragility in AS melts is linked to specific local coordination environments.