| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystallized glass substrate for an information recording medium having various properties, in particular high fracture toughness, required for the application of the substrate for the information recording medium in next generation represented by a perpendicular magnetic recording system and the like, a material excellent in workability for such a purpose and the substrate for the information recording medium where bubbles in a glass blank and reboiling in direct pressing are not generated without practically employing arsenic and antimony components adversely affecting human bodies and the environment, which is suitable for a direct pressing method and where productivity is high.SOLUTION: The substrate for the information recording medium consisting of crystallized glass includes one or more selected from among RAlOand RTiO(wherein, R is one or more selected from among Zn, Mg and Fe) as a main crystal phase, has a crystal grain size in the main crystal phase of 0.5-20 nm, has a crystallinity of 15% or less and has a specific gravity of 3.00 or less. |
