Glass composition for crystallized glass
OwnerHideki Nagata, Hiroshi Yuki +3inventors
InventorsHideki Nagata, Hiroshi Yuki, Toshiharu Mori, Hideki Kawai, Kazuhiko Ishimaru
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Abstract
A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.
Claims40
A polished glass disk medium substrate formed of a mixture of glass forming raw materials comprising
- about 40.5% to about 43.5% by weight SiO2;
- about 5% to about 19.5% by weight Al2O3;
- about 10% to about 30% by weight MgO;
- and
- about 5% to about 20% by weight TiO2.
The polished glass disk medium substrate according to claim 22, wherein the crystalline phase of enstatite represents less than or equal to about 20 percent by weight of the crystalline phases.
A method of making a glass disk medium substrate comprising:
- heating glass forming raw materials to a temperature sufficiently high to melt the raw materials;
- forming a disk medium substrate;
- and
- crystallizing the disk medium substrate, wherein said crystallizing comprises heating the disk medium substrate to a temperature, T1, between about 500 and 680° C. to generate crystal nuclei;
- heating at a temperature, T2, between about 680 and about 800° C. to grow crystal nuclei;
- and cooling to obtain crystalized glass.
Dependencies are inferred from the claim text.