High coercivity, cobalt-doped ferrimagnetic iron oxide particulates
US4371567A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1981 |
| Grant date | Feb 1, 1983 |
| Priority date | — |
| Expiry date | Apr 7, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/70626
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Highly coercive, cobalt-doped ferrimagnetic iron oxide particulates comprised of ferrous iron and well-adapted for the manufacture of various magnetic recording media, are prepared by (i) thermally decomposing a .beta.-diketone/cobalt complex onto fluidized iron oxide particles having the formula (FeO).sub.x Fe.sub.2 O.sub.3, wherein 0.ltoreq.x.ltoreq.1.5, (ii) next annealing the particulates which result at a temperature ranging from about 300.degree. to 500.degree. and then (iii) permitting the same to cool, while at the same time sweeping the cooling zone with an inert gas, and then (iv) controlledly re-oxidizing the annealed/cooled particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.