Patent · US Expired

Process for the manufacture of ferromagnetic chromium dioxide

US4340494A · kind A · utility

6Cited by

4References

4Claims

0Family size

Assignee

BASF SE

Inventors

Manfred Ohlinger · Bischofswerda, DE
Guenter Vaeth · Schifferstadt, DE
Norbert Mueller · Ostseebad Nienhagen, DE
Eugen Wettstein · Germersheim, DE

Key dates

Filing date	Oct 21, 1980
Grant date	Jul 20, 1982
Priority date	—
Expiry date	Oct 21, 2000

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/80
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A process for the manufacture of ferromagnetic chromium dioxide modified with foreign elements, by reacting oxides of trivalent and hexavalent chromium under superatmospheric pressure at an elevated temperature in the presence of water and of antimony(III) oxide as modifier, with or without other modifiers in an amount not exceeding 15% by weight, wherein the antimony(III) oxide employed as modifier is, to the extent of more than one-third, present as the senarmontite cubic modification, has a specific surface area, measured by the BET method, of from 1.5 to 15 m.sup.2 /g, and is added in a total amount of up to 0.5% by weight, based on the resulting chromium dioxide.

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