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AssigneeHoya Corporation
InventorsKoichi SATO, Kazuaki HASHIMOTO
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Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, in which the total content of Li2O, Na2O, K2O, B2O3, and ZnO (Li2O + Na2O + K2O + B2O3 + ZnO) is in a range of 0 mol% or more and 3 mol% or less, the mole ratio of the total content of Al2O3 and MgO relative to the total content of SiO2 and CaO [(Al2O3 + MgO) / (SiO2 + CaO)] is in a range of 0.30 or more and 0.6 or less, the total content of SiO2 and Al2O3 (SiO2 + Al2O3) is in a range of 64 mol% or more and 85 mol% or less, and the total content of SiO2, Al2O3, MgO, and CaO (SiO2 + Al2O3 + MgO + CaO) is in a range of 87 mol% or more and 98 mol% or less.
A glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, wherein the total content of Li2O, Na2O, K2O, B2O3 and ZnO (Li2O + Na2O + K2O + B2O3 + ZnO) is in a range of 0 mol% or more and 3 mol% or less, a mole ratio of the total content of Al2O3 and MgO relative to the total content of SiO2 and CaO [(Al2O3 + MgO) / (SiO2 + CaO)] is in a range of 0.30 or more and 0.6 or less, the total content of SiO2 and Al2O3 (SiO2 + Al2O3) is in a range of 64 mol% or more and 85 mol% or less, and the total content of SiO2 Al2O3 MgO, and CaO (SiO2 + Al2O3 + MgO + CaO) is in a range of 87 mol% or more and 98 mol% or less.
A glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, wherein a mole ratio of the total content of Al2O3 and MgO relative to the total content of SiO2 and CaO [(Al2O3 + MgO) / (SiO2 + CaO)] is in a range of 0.30 or more and 0.6 or less,
Dependencies are inferred from the claim text.