Patent · US Expired

Acicular iron-magnet pigments having an adjustable coercive field strength and process for producing same

US5240515A · kind A · utility

0Cited by

1References

6Claims

0Family size

Assignee

Studiengesellschaft Kohle gGmbH · DE

Inventors

Helmut Bonnemann · Neheim, DE
Werner Brijoux · Oberhausen, DE
Rainer Brinkmann · Wetter (Ruhr), DE

Key dates

Filing date	May 18, 1992
Grant date	Aug 31, 1993
Priority date	—
Expiry date	May 18, 2012

Classification

Technology area (CPC G)Physics
CPC primaryG11B5/70615
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

Disclosed is a process for preparing acicular non-sintered iron metal pigments for magnetic signal recording, having a high storage density, high saturation magnetization and remanence, the coercive field strength of which at a given crystallite size of the starting material is low and is increased as desired by subsequent annealing. The preparation of said iron metal pigments is effected by reduction of iron oxide compounds with metal hydrides of metals of the Groups I or II of the Periodic Table of Elements in organic solvents, with the metal hydrides being solvatized with a carrier in the form of a carrier complex.

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