Patent · US Expired

Manufacture of acicular cobalt-containing magnetic iron oxide

US4287233A · kind A · utility

9Cited by

4References

4Claims

0Family size

Assignee

BASF SE

Inventors

Peter Rudolf · Ludwigshafen, DE
Werner Steck · Ludwigshafen, DE
Eberhard Koester · Bischofswerda, DE
Manfred Ohlinger · Bischofswerda, DE
Christof Jaeckh · Heidelberg, DE

Key dates

Filing date	Jan 29, 1980
Grant date	Sep 1, 1981
Priority date	—
Expiry date	Jan 29, 2000

Classification

Technology area (CPC G)Physics
CPC primaryG11B5/70657
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A process for the manufacture of acicular magnetic iron oxide consisting of core of gamma-iron(III) oxide and a ferrite shell which contains, based on the total amount of magnetic material, from 0.2 to 12 per cent by weight of cobalt(II) ions and from 0.1 to 15 per cent by weight of iron(II) ions, wherein a precipitate of cobalt(II) hydroxide and iron (II) hydroxide is applied to acicular gamma-iron(III) oxide particles and the latter are heated at 100.degree.-200.degree. C.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.