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:
Apr. 18, 1989
Filed:
Nov. 06, 1986
Jeries I Bishara, Mentor, OH (US);
Anthony J Vaccaro, Madison, OH (US);
Eric J Rudd, Painesville, OH (US);
ELTECH Systems Corporation, Boca Raton, FL (US);
Abstract
A highly magnetic isotropic iron oxide powder with a uniform particle size distribution and particle size in the range from 0.005 to 0.2 micrometer consists of a mixed iron oxide exhibiting gamma (Fe.sub.2 O.sub.3) and ferrite (Fe.sub.3 O.sub.4) structure, having the empirical formula Fe.sub.72-x O.sub.96, where x has a value between 2 to 7, an aspect ratio of at most 2:1 and a temperature coefficient of coercivity of less than -0.7% per degree Celcius. The mixed oxide is optionally a cobalt-modified mixed iron oxide containing 2-6% by weight of cobalt and is obtained by heating ultrafine, ferrite particles in a controlled, oxidizing atmosphere at a temperature of 240.degree. C. to 320.degree. C. for a period of one to three hours.