Magnetic recording medium
US6103340A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1998 |
| Grant date | Aug 15, 2000 |
| Priority date | — |
| Expiry date | Sep 10, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/256
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium comprising a nonmagnetic substrate having provided thereon an intermediate layer consisting essentially of magnetic powder having a Mohs hardness of not less than 3 and an average particle size of not greater than 0.5 .mu.m and/or nonmagnetic powder having a Mohs hardness of not less than 3, carbon black, and a binder and, as a top layer, a magnetic layer consisting essentially of ferromagnetic metal powder and a binder, in which said magnetic layer has an average center-line surface roughness (Ra) of not greater than 7 nm, and said magnetic layer has an average center-line surface roughness (Ra) of 10 to 30 nm after being immersed in a hydrochloric acid aqueous solution for 24 hours.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.