Glass-ceramic substrate for a magnetic information recording medium
US6387509B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1999 |
| Grant date | May 14, 2002 |
| Priority date | — |
| Expiry date | Feb 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/73921
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A glass-ceramic substrate for a magnetic information recording medium contains, as a main crystal phase or phases, one or more crystal phases selected from the group consisting of &bgr;-quartz (&bgr;-SiO2), &bgr;-quartz solid solution (&bgr;-SiO2 solid solution), &bgr;-spodumene (&bgr;-Li2O.Al2O3.4SiO2), &bgr;-spodumene solid solution (&bgr;-Li2O.Al2O3.4SiO2 solid solution), &bgr;-eucryptite (&bgr;-Li2O.Al2O3.2SiO2, a part of Li2O being capable of being substituted by MgO and/or ZnO) and &bgr;-eucryptite solid solution (&bgr;-Li2O.Al2O3.2SiO2 solid solution, a part of Li2O being capable of being substituted by MgO and/or ZnO). Alternatively, the glass-ceramic contains, as a main crystal phase or phases, gahnite (ZnAl2O4) and/or gahnite solid solution (ZnAl2O4 solid solution). The glass-ceramic substrate has a high heat resisting property and a super flat surface capable of achieving a high recording density according to the perpendicular magnetic recording.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.