The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 08, 1990
Filed:
Aug. 31, 1987
Fritz Rodi, Moers, DE;
Peter Kiemle, Krefeld-Traar, DE;
Aloys Eiling, Bochum, DE;
Hendrik Kathrein, Juchen-Aldenhoven, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
Magnetic iron oxide pigments having a monomolecular coating of a cobalt compound useful in magnetic signal recordings having a dependence of coercivity on temperature in the temperature range of from 76 K to 298 K of less than 0.13 kA/mK and having a coercivity on powder compressed to 0.9 g/cm.sup.3 of greater than 51 kA/m are prepared applying a preliminary coating of Fe.sub.3 O.sub.4 or a bertholloid compound to a magnetic iron oxide core material having the composition FeO.sub.x where x is a number from 1.33 to 1.55 and then covering the preliminary coating with a cobalt compound.