| 发明名称 |
GLASS FOR MAGNETIC RECORDING MEDIUM SUBSTRATE AND MAGNETIC RECORDING MEDIUM SUBSTRATE |
| 摘要 |
A glass for a magnetic recording medium substrate, which contains SiO2, Li2O, Na2O, and MgO as essential components; alkali metal oxides selected from the group consisting of Li2O, Na2O, and K2O of 6 to 15 mol % in total; alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO of 10 to 30 mol % in total. A molar ratio of a content of Li2O to a total content of alkali metal oxides {Li2O/(Li2O+Na2O+K2O)} is greater than 0 and less than or equal to 0.3; a molar ratio of a content of MgO to a total content of alkaline earth metal oxides {MgO/(MgO+CaO+SrO+BaO)} is greater than or equal to 0.80; a glass transition temperature is greater than or equal to 650° C.; and a Young's modulus is greater than or equal to 80 GPa. |
| 申请公布号 |
US2016225396(A1) |
申请公布日期 |
2016.08.04 |
| 申请号 |
US201415021204 |
申请日期 |
2014.09.10 |
| 申请人 |
HOYA CORPORATION |
发明人 |
SHIMOJIMA Shoji |
| 分类号 |
G11B5/73;C03C3/085;C03C21/00 |
主分类号 |
G11B5/73 |
| 代理机构 |
|
代理人 |
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| 主权项 |
1. Glass for a magnetic recording medium substrate, which comprises:
SiO2, Li2O, Na2O, and MgO as essential components; alkali metal oxides selected from the group consisting of Li2O, Na2O, and K2O of 6 to 15 mol % in total; alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO of 10 to 30 mol % in total; wherein a molar ratio of a content of Li2O to a total content of the alkali metal oxides {Li2O/(Li2O+Na2O+K2O)} is greater than 0 and less than or equal to 0.3; a molar ratio of a content of MgO to a total content of the alkaline earth metal oxides {MgO/(MgO+CaO+SrO+BaO)} is greater than or equal to 0.80; a glass transition temperature is greater than or equal to 650° C.; and a Young's modulus is greater than or equal to 80 GPa. |
| 地址 |
Tokyo JP |
