Recording disk substrate members and process for producing same
US4690846A · kind A · utility
20Cited by
6References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1985 |
| Grant date | Sep 1, 1987 |
| Priority date | — |
| Expiry date | Jul 26, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A substrate member for recording disk characterized in that a glass coating film is provided on an alumina base ceramic material having micropores of no larger than 5 microns and a relative theoretical density of no less than 96%, said glass coating film having a surface roughness of no more than 80 angstroms, being substantially pore-free and strain-free on the surface, and having a thickness of 0.3 to 200 microns and a relative difference of no more than 10.sup.-6 /deg in the coefficient of thermal expansion with respect to said base material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.