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:
Aug. 10, 1976
Filed:
Nov. 02, 1973
Applicant:
Inventors:
Peter Woditsch, Krefeld, DT;
Kurt Hill, Krefeld, DT;
Franz Hund, Krefeld-Bockum, DT;
Fritz Rodi, Kaldenhausen, DT;
Assignee:
Bayer Aktiengesellschaft, , DT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01G / ;
U.S. Cl.
CPC ...
252 6256 ; 423634 ;
Abstract
Process for producing ferromagnetic iron oxides whereby a solution of a ferrous salt is oxidized in the presence of .alpha.-FeO(OH) seed, a basic precipitant, and phosphoric acid or a water soluble salt thereof to form .alpha.-FeO(OH), which can be dehydrated, optionally tempered, reduced and re-oxidized to needle-shaped .gamma.-Fe.sub.2 O.sub.3. The resulting product has high coercive force values which make it especially useful for magnetic impulse recording and reproduction.