Glass-ceramics for magnetic disc substrate, magnetic disc substrate and magnetic disc
US5872069A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Dec 19, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/73921
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A novel Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which can prevent deformation of the substrate at a large temperature change and provide a strong, small and compact magnetic disc substrate without trouble and much reading and/or writing informations on the smoothened surface of the substrate, is provided. The glass-ceramics has a main crystal phase of lithium disilicate (Li.sub.2 O.2SiO.sub.2) phase, the peak intensity I of cristobalite phase (CRI) of at least 20 but not more than 50 when the peak intensity of I of lithium disilicate (L2S) phase measured by an X-ray diffraction analysis is taken as 100, and containing 1.0-3.0 parts by weight of Cr.sub.2 O.sub.3 and 1.0-3.0 parts by weight of MnO when the sum of metal oxides other than Cr.sub.2 O.sub.3 and MnO is taken as 100 parts by weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.