Pressure-driven homogenization of lithium disilicate glasses

TL;DR

This study uses molecular dynamics simulations and experiments to investigate how pressure influences phase separation and heterogeneity in lithium disilicate glasses, revealing that higher pressure reduces heterogeneity and affects nucleation behavior.

Contribution

The paper provides new insights into the pressure-dependent atomistic mechanisms of phase separation in lithium disilicate glasses, combining simulations with experimental validation.

Findings

Heterogeneity decreases with increasing pressure.

Almost complete homogenization occurs around 30 GPa.

Li cation clustering channels diminish as pressure increases.

Abstract

Lithium disilicate glasses and glass-ceramics are good potential candidates for biomedical applications and solid-state batteries, and serve as models of nucleation and crystal growth. Moreover, these glasses exhibit a phase separation that influences their nucleation and crystallization behavior. The atomistic mechanisms of the phase separation and their pressure dependence are unclear so far. Here, we used molecular dynamics simulations supported by experiments to assess the spatial heterogeneity of lithium disilicate glasses prepared under pressure. We show that the glass heterogeneity decreases with increasing the cooling pressure and almost disappears at pressures around 30 GPa. The origin of the heterogeneity is due to the attraction between Li cations to form clustering channels, which decreases with pressure. Through our results, we hope to provide valuable insights and guidance for making glass-ceramics with controlled crystallization.