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ABSTRACT Soda–lime silicate (SLS) glass is widely used in commercial applications due to its low cost and adequate mechanical and optical properties. This study combined glass‐ceramic technology with ion‐exchange (IOX) processing to enhance the mechanical performance of 0.15Na2O–0.15CaO–0.7SiO2SLS glass while maintaining its optical transparency. Transparent SLS glass‐ceramics (SLS‐GCs) were produced by controlling the nucleation and growth of the parent SLS glass, with crystallinity tailored by varying growth times. The resulting SLS‐GCs exhibited surface crystallization, with devitrite (Na2Ca3Si6O16) as the primary crystalline phase and cristobalite (SiO2) as a minor phase. Both the crystalline layer thickness and crystallite size increased with longer growth times. During the subsequent IOX process in a molten KNO3bath, Na+to K+exchange primarily occurred in the glassy phase. Although higher crystallinity hindered K+diffusion and resulted in a thinner ion‐exchanged layer, it simultaneously enhanced mechanical strength by increasing hardness and reducing crack probability. In contrast, the elastic moduli decreased with higher crystallinity, likely due to thermal expansion mismatch between the glass matrix and devitrite crystallites. Despite a slight decline in transmittance after crystallization and IOX, all samples retained high optical transparency, demonstrating their potential for applications that demand both mechanical durability and visual clarity.
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This content will become publicly available on May 1, 2027
Binary Rare‐Earth Silicate Glasses Near Deep Eutectic: The Case for Sc 2 O 3 –SiO 2 System
ABSTRACT Homogeneous glass formation in binary rare‐earth silicate systems has thus far been precluded due to the presence of extensive liquid–liquid immiscibility and a strong tendency of these liquids toward crystallization. In this study, we demonstrate homogeneous glass formation in the Sc2O3–SiO2binary system within a narrow compositional window (37–39 mol% Sc2O3) near a deep eutectic between the compounds Sc2Si2O7and Sc2SiO5, using containerless laser melting under aerodynamic levitation. The atomic structure of these unusual glasses is investigated using multinuclear (29Si,45Sc,17O) solid‐state nuclear magnetic resonance (NMR) and Raman spectroscopy. The spectroscopic results, when taken together, provide a comprehensive picture of the structure of these glasses characterized by pyrosilicate [Si2O7]6−anionic units interconnected by Sc cations in ScO6coordination polyhedra, via Si–O–Sc linkages. A significant fraction (∼6%) of the oxygen atoms in the structure is present as free oxide (FO) ions in Sc–O–Sc linkages, providing connectivity between the ScO6polyhedra. The formation of the FO species via oxygen disproportionation reaction is promoted by the uniquely high field strength of the Sc3+ions, and the resulting structural frustration is hypothesized to suppress crystallization of the stable pyrosilicate phase in these liquids, enabling glass formation in an otherwise non‐glass‐forming binary system. These findings highlight the critical role of rare‐earth cation field strength in controlling oxygen speciation, structure, and glass‐forming ability in this binary silicate system.
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- Award ID(s):
- 2409281
- PAR ID:
- 10687546
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 109
- Issue:
- 5
- ISSN:
- 0002-7820
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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