Method of providing hexagonal ferrite magnetic powder with enhanced coercive force stability
US5686137A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1996 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Mar 25, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2982
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An object of the present invention is to provide a magnetic powder for magnetic recording and a magnetic recording medium wherein stability of a coercive force of each of the magnetic powder and the magnetic recording medium is improved. The magnetic powder for magnetic recording and the magnetic recording medium having the magnetic powder used therfor are characterized in that the magnetic powder is composed mainly of a plate-shaped ferrite having a crystalline anisotropy and containing an element effective for reducing a temperature coefficient of coercive force of the magnetic powder, and that a difference between a coercive force (Hc) of the magnetic powder at a room temperature and a coercive force (Hc(s)) of the magnetic powder in such a state that the magnetic powder is dispersively deposited on the surface of silica (SiO.sub.2) powder particles is 100 (Oe) or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.