Melt-quenched oxide glasses with ultrahigh Young's modulus and small thermal expansion coefficient

The well-known Makishima–Mackenzie relationship, consisting of two terms of the dense packing structure and dissociation energy regarding bonding in constituent oxides, enables fabricating oxide glasses with ultrahigh Young's modulus (～140 GPa) and a small coefficient of thermal expansion (CTE) (～4 ppm/K). The effects of increasing MgO and Ta₂O₅ contents in an MgO–Ta₂O₅–Al₂O₃–SiO₂–B₂O₃ glass system using a conventional melt-quenching method are revealed. The essential oxides of Al₂O₃ and Ta₂O₅ are primarily suitable for dense packing structures dominated by a large coordination number of oxygens. The substitution of CaO by MgO results in high dissociation energy when the glass composition falls in the peraluminous regime (Al₂O₃/MgO + CaO] > 1). A small CTE is realized by increasing the molar ratio of Al₂O₃/MgO. According to magic-angle spinning-nuclear magnetic resonance spectra, mechanically and thermally functional oxide glasses depend on their structures. These findings facilitate the development of glass substrate applications without thermal dilatation.