Glass composition and substrate for information recording media comprising the same
AssigneeNippon Sheet Glass Co., Ltd.
InventorsJunji Kurachi, Akihiro Koyama, Shoichi Kishimoto, Nobuyuki Yamamoto
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Abstract
A glass composition is disclosed which has a high modulus of elasticity (Young's modulus) and a high rigidity (modulus of elasticity/specific gravity) and is capable of being effectively inhibited from bending or vibrating. Also disclosed is a substrate for information recording media which comprises the glass composition. The glass composition comprises the following components, in terms of mol %: 55 to 65% SiO2, 0.5 to less than 6% Al2O3, 12 to 22% Li2O, 0 to 5% Na2O, 0 to 10% TiO2, 0 to 3% ZrO2, 0 to 8% MgO, 0 to 18% CaO, and 0 to 6% SrO, provided that the content of RO (RO=MgO+CaO+SrO) is 5 to 18%.
Claims8
A glass composition consisting of the following components, in terms of mol %:
- 55 to 65% SiO2,
- 0.5 to less than 6% Al2O3,
- 12 to 22% Li2O,
- 0 to 5% Na2O,
- 0 to 10% TiO2,
- 0 to 3% ZrO2,
- O to 8% MgO,
- 0 to 18% CaO, and
- 0 to 6% SrO,
- provided that the content of RO (RO=MgO+CaO+SrO) is 5 to 18% and at least one of As2O3, Sb2O3, SO3, SnO2, Fe2O3, CoO, Cl, F, K2O, and Y2O3 is amount of up to 3 mol %, and wherein the proportion of Na2O to Li2O is in the range of from {fraction (1/1)} to ⅕ and that of MgO to CaO is in the range of from ¼ to {fraction (1/1)}.
Dependencies are inferred from the claim text.