A new perspective for nucleation and nanocrystallization from interfacial energy and nanoscale composition fluctuations in glasses

Abstract

Nucleation behaviors in glasses/supercooled liquids (SCLs) such as lithium disilicate Li2O–2SiO2, cordierite Mg2Al4Si5O18, fresnoite Ba2TiSi2O8, and K2O–Nb2O5–GeO2/TeO2 glasses were analyzed and discussed from the interfacial energy γ at SCL–nucleus interfaces and nanoscale composition fluctuations. Based on the fragility concept for SCLs and the intrinsic origin of γ, the magnitude order of γ(fragile SCL) < γ(strong SCL) was proposed to be a crucial guide for an understanding of high homogeneous nucleation rates and prominent nanocrystallization. The role of nucleating agent TiO2/ZrO2 in accelerating the nucleation rate in cordierite‐based and β‐spodumene‐type Li2O–Al2O3–SiO2‐based glasses was discussed from the new perspective of γ(homoepitaxial‐like nucleation) < γ(heteroepitaxial‐like nucleation). Ferroelectric nanocrystals such as SrxBa1–xNb2O6 in borate glasses and fluoride nanocrystals such as CaF2 are also well understood from the proposed guidelines. The present article provides a new perspective for nucleation in glasses/SCLs, contributing to the comprehensive composition design of new innovative glass‐ceramics.