Glass-ceramic substrate for a magnetic information storage medium
US5972816A · kind A · utility
37Cited by
13References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 5, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Nov 5, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/73921
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A glass-ceramic substrate for a magnetic information storage medium such as a magnetic disk having a super flatness suited for a contact recording system includes a SiO.sub.2 --Al.sub.2 O.sub.3 --Li.sub.2 O system glass-ceramic and has either .beta.-quartz solid solution (.beta.-SiO.sub.2 solid solution) or a mixture of .beta.-quartz solid solution (.beta.-SiO.sub.2 solid solution) and .beta.-spodumene solid solution (.beta.-Li.sub.2 O.Al.sub.2 O.sub.3.4SiO.sub.2 solid solution) as its main crystal phase. The surface roughness (Ra) of the glass-ceramic substrate after polishing is within a range from 1 .ANG. to 5 .ANG..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.