| 摘要 |
PROBLEM TO BE SOLVED: To provide a new glass material exhibiting high specific elastic modulus, having a composition of SiO2 -Al2 O3 -RO (R is a bivalent metal) and useful as a base for an information recording medium such as a magnetic disk base, a base for an information recording medium made of the material and an information recording medium produced by using the base. SOLUTION: This material to be used as a material for an information recording medium is made of a glass having a composition of SiO2 -Al2 O3 ,-RO (R is a bivalent metal). In this case, the glass contains >=20mol% of A1.03 , >=20mol% of MgO as RO or e.g. 0.5-17mol% of Y2 O3 . This base for an information recording medium is composed of the above material. The magnetic disk is composed of the above base and at least a magnetic layer formed on the base. |
