Glass-ceramic substrate for a magnetic disk
US5866489A · kind A · utility
42Cited by
5References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Feb 3, 1997 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Feb 3, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/8404
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2 O . 2SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.