Substrates for magnetic discs, magnetic discs and process for producing magnetic discs
US6048589A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Nov 9, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24355
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A magnetic disc substrate is provided, which includes a magnetic disc substrate body made of glass and is characterized in that a metal element capable of absorbing light in at least a surface portion of the magnetic disc substrate body, and a texture is formed on a surface of the magnetic disc substrate body. Ions of the metal element are dispersed in the surface portion of the magnetic disc substrate, or the metal element is contained in a composition of the glass constituting the magnetic disc substrate in the form of an oxide. The glass is preferably a crystallized glass a Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 based crystallized glass, which particularly preferably contains 65 to 85 wt % of SiO.sub.2, 8 to 15 wt % of Li.sub.2 O, 2 to 8 wt % of Al.sub.2 O.sub.3, 1 to 5 wt % of P.sub.2 O.sub.5 and 1 to 10 wt % of ZrO.sub.2 and has lithium disilicate (Li.sub.2 O.2SiO.sub.2) as a main crystalline phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.