Magnetic recording medium comprising an underlayer containing .alpha.-iron oxide powder and a magnetic layer containing ferromagnetic metallic powder
US5496622A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 26, 1994 |
| Grant date | Mar 5, 1996 |
| Priority date | — |
| Expiry date | Jul 26, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2991
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a magnetic recording medium which comprises a non-magnetic support and a layer containing .alpha.-iron oxide powder as a lower layer and a layer containing ferromagnetic powder as an upper layer which are provided on the non-magnetic support in this order from a side of the non-magnetic support, wherein weight ratios of elements in the whole composition of the .alpha.-iron oxide powder are 0.05 to 5 parts by weight of aluminum (Al) atom and 0.05 to 5 parts by weight of silicon (Si) atom based on 100 parts by weight of iron (Fe) atom, and average existence ratios of elements in terms of the number of atoms forming the surface of the .alpha.-iron oxide powder are 40 or less of Al atom and 1 to 60 of Si atom based on the number of Fe atom as 100.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.