Patent · US Expired

Preparation of cobalt-containing isotropic magnetic iron oxides

US4755315A · kind A · utility

1Cited by

5References

1Claims

0Family size

Assignee

BASF SE

Inventors

Werner Steck · Ludwigshafen, DE
Rainer Feser · Havelsee, DE
Helmut Jakusch · Bischofswerda, DE
Peter Rudolf · Ludwigshafen, DE
Guenter Vaeth · Schifferstadt, DE
Udo Kullmann · Dirmstein, DE

Key dates

Filing date	Feb 12, 1987
Grant date	Jul 5, 1988
Priority date	—
Expiry date	Feb 12, 2007

Classification

Technology area (CPC G)Physics
CPC primaryG11B5/70673
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A process for the preparation of cobalt-containing isotropic magnetic iron oxides which are based on gamma-iron(III) oxide, contain from 2 to 7% by weight of cobalt(II) ions and less than 2% by weight of Fe(II) ions, the percentages in each case being based on the iron oxide, and have a particle length of from 0.08 to 0.30 .mu.m, a length/width ratio of from 1.5 to 3.5:1 and a specific remanent magnetization after saturation of not less than 60 nTm.sup.3 /g.

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