Crystallized glass substrate for information recording medium and method of producing the same

摘要

To provide a substrate for information recording medium having various properties, in particular higher fracture toughness, required for application of the substrate for information recording medium of the next generation such as perpendicular magnetic recording system, etc. and a material with excellent workability for such purpose. A crystallized glass substrate for information recording medium, consisting of a crystallized glass which comprises one or more selected from RAl2O4 and R2TiO4 as a main crystal phase, in which R is one or more selected from Zn, Mg and Fe, and in which the main crystal phase has a crystal grain size in a range of from 0.5 nm to 20 nm, a degree of crystallinity of 15% or less, and a specific gravity of 3.00 or less.

主权项

1. A crystallized glass substrate for information recording medium, consisting of a crystallized glass which comprises the components of
SiO2 of from 40% to 60%, Al2O3 of from 7% to 19%, and ZnO of from 5% to 25%, RO of from 5% to 35% in terms of % by mass on the oxide basis, wherein R is one or more selected from Zn, Mg and Fe, and B2O3 of from 3.0% to less than 8%, and which comprises one or more selected from RAl2O4 and R2TiO4 as a main crystal phase, wherein R is one or more selected from Zn, Mg and Fe, and wherein the main crystal phase has a crystal grain size in a range of from 0.5 nm to 20 nm, a degree of crystallinity of 15% or less, and a specific gravity of 3.00 or less.