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:
Feb. 01, 1983
Filed:
Apr. 07, 1981
Applicant:
Inventors:
Assignee:
Rhone-Poulenc Industries, Paris, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C01G / ;
U.S. Cl.
CPC ...
427130 ; 427127 ; 427213 ; 252 6256 ;
Abstract
Highly coercive, cobalt-doped ferrimagnetic iron oxide particulates comprised of ferrous iron and well-adapted for the manufacture of various magnetic recording media, are prepared by (i) thermally decomposing a .beta.-diketone/cobalt complex onto fluidized iron oxide particles having the formula (FeO).sub.x Fe.sub.2 O.sub.3, wherein 0.ltoreq.x.ltoreq.1.5, (ii) next annealing the particulates which result at a temperature ranging from about 300.degree. to 500.degree. and then (iii) permitting the same to cool, while at the same time sweeping the cooling zone with an inert gas, and then (iv) controlledly re-oxidizing the annealed/cooled particles.