Patent · US Expired

Manufacture of acicular ferrimagnetic iron oxides

US4221776A · kind A · utility

7Cited by

4References

2Claims

0Family size

Assignee

BASF SE

Inventors

Horst Autzen · Freinsheim, DE
Helmut Jakusch · Bischofswerda, DE
Eberhard Koester · Bischofswerda, DE
Werner Loeser · Ludwigshafen, DE
Peter Rudolf · Ludwigshafen, DE
Wilhelm Sarnecki · Schifferstadt, DE
Werner Steck · Ludwigshafen, DE

Key dates

Filing date	Jan 25, 1979
Grant date	Sep 9, 1980
Priority date	—
Expiry date	Jan 25, 1999

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/42
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A process for the manufacture of acicular ferrimagnetic iron oxide by reducing heat-treated acicular iron(III) oxide hydroxide with an organic compound which decomposes in the presence of iron oxide at from 450.degree. to 650.degree. C., followed by at least partial oxidation with an oxygen-containing gas at from 200.degree. to 500.degree. C., wherein the iron(III) oxide hydroxide employed is heat-treated at from 450.degree. to 700.degree. C. and has a surface area, measured by the BET method, of from 10 to 23 m.sup.2 /g.

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