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. 25, 2003
Filed:
Apr. 29, 1998
Helmut Mangold, Rodenbach, DE;
Werner Hartmann, Babenhausen, DE;
Dieter Kerner, Midland Park, NJ (US);
Peter Kleinschmit, Hanau, DE;
Degussa AG, Düsseldorf, DE;
Abstract
Pyrogenically, especially flame-hydrolytically produced zirconium dioxide powder with a specific surface area between 20 and 200 m /g, a primary particle size between 7 and 100 nm, a tamped density of the deacidified and non-deacidified zirconium dioxide between 40 and 150 g/l with Sears numbers of the deacidified and non-deacidified zirconium dioxide between 1 and 20 ml/2 g and with a chlorine content of the deacidified zirconium dioxide less than 0.6% by weight. These are produced by evaporating zirconium halides, mixing the vapors alone or together with a carrier gas in a burner with air, oxygen, nitrogen and hydrogen, causing the gases to react with each other in a flame in a closed burner chamber, cooling off the waste gases and the zirconium dioxide in a heat exchanger unit, separating the waste gases from the zirconium dioxide and removing any halide remnants adhering to the zirconium dioxide by a heat treatment with moistened air.