Patent · US Expired

Manufacture of acicular ferromagnetic iron particles

US4344791A · kind A · utility

8Cited by

9References

2Claims

0Family size

Assignee

BASF SE

Inventors

Werner Steck · Ludwigshafen, DE
Wilhelm Sarnecki · Schifferstadt, DE
Laszlo Marosi · Ludwigshafen, DE
Manfred Ohlinger · Bischofswerda, DE
Werner Loeser · Ludwigshafen, DE

Key dates

Filing date	Jul 31, 1980
Grant date	Aug 17, 1982
Priority date	—
Expiry date	Jul 31, 2000

Classification

Technology area (CPC H)Electricity
CPC primaryH01F1/061
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A process for the manufacture of acicular ferromagnetic iron particles by heating a goethite, provided with a shape-stabilizing surface coating, at 250.degree.-450.degree. C. in an atmosphere containing water vapor at a partial pressure of not less than 30 mbar, to give alpha-iron(III) oxide, and reducing this material with hydrogen at 275.degree.-425.degree. C., and the use of the iron particles thus obtained as magnetic material in the production of magnetic recording media.

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