Magnetic recording medium
US5582910A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 1995 |
| Grant date | Dec 10, 1996 |
| Priority date | — |
| Expiry date | Feb 6, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium having improved electromagnetic characteristics and running properties is disclosed. The magnetic recording medium comprises a non-magnetic support having thereon a plurality of magnetic layers consisting of two or more layers composed of a first lower magnetic layer and a second upper magnetic layer, provided on said support by either co-coating the lower magnetic layer and the upper magnetic layer in the wet state, or coating the lower magnetic layer and then the upper magnetic layer while the lower magnetic layer is still in the wet state; wherein the cobalt-modified iron oxide is employed as the ferromagnetic powder contained in the lower magnetic layer, ferromagnetic metal is employed as the ferromagnetic powder contained in the upper magnetic layer, both the ferromagnetic powder contained in the lower magnetic layer and the ferromagnetic powder contained in the upper magnetic layer having an average major axis length of 0.25 .mu.m or less and an average acicular ratio of 10 or less, a difference in the average major axis length between the ferromagnetic powder contained in the lower magnetic layer and that contained in the upper magnetic layer of 0…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.