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:
Oct. 19, 1993
Filed:
Sep. 18, 1992
Degussa Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
Brown spinel pigments based on zinc chromite which are iron-free and exhibit an atomic ratio of chromium to zinc in a range of 1 to greater than 0.5 up to 2 are disclosed. Preferred pigments additionally contain manganese, in which instance the atomic ratio of Mn to Cr is a maximum of 0.2. The production of the pigments involves a firing process of a powder mixture consisting of the oxides the metals, or precursors thereof, contained in the pigment. Instead of previously known grayish-brown unattractive products, attractive brown pigments are obtained by means of the selected molar ratio and a baking temperature above 1200.degree. C. The novel pigments can be used in the presence of glass frits even at firing temperatures above 1200.degree. C. to 1500.degree. C. and are suitable for a common firing of ceramic carrier and decoration.