Patent · US Expired

Acicular cobalt-modified iron oxides and their preparation

US5183709A · kind A · utility

7Cited by

9References

2Claims

0Family size

Assignee

BASF SE

Inventors

Ekkehard Schwab · Neustadt, DE
Ronald J. Veitch · Frankenthal (Pfalz), DE
Helmut Auweter · Schifferstadt, DE

Key dates

Filing date	May 21, 1990
Grant date	Feb 2, 1993
Priority date	—
Expiry date	May 21, 2010

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T428/2993
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

Acicular, cobalt-modified iron oxides consisting of a core of an iron oxide of the formula FeO.sub.x where x is from 1.33 to 1.5 and a ferrite shell which contains a total amount of from 0.4 to 12% by weight of cobalt ions and not more than 5% by weight of iron(II) ions, the percentages being based on the total amount of the material, which iron oxides have improved aging resistance, particularly with regard to the coercive forces, and a process for their preparation.

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