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:
Mar. 16, 1993
Filed:
May. 09, 1991
Dietrich Speer, Hanau, DE;
Akos Kiss, Alzenau-Wasserlos, DE;
Peter Kleinschmit, Hanau, DE;
Jenny Horst, Gelnhausen, DE;
Degussa AG, Hanau, DE;
Abstract
Coated spinel color pigments with a core of a colored spinel, in particular CoAl.sub.2 O.sub.4, and a coating glassy layer of a silicate are described. The coating layer is essentially silicon dioxide and one or more oxides of the group of alkali metals, alkaline earth metals, and/or earth metals show a high resistance to bleeding in the presence of glass fluxes, as compared to uncoated spinels. The pigments are produced by sintering, for 0.5 to 5 hours, a powder mixture of the spinel, silicon dioxide, and at least one member chosen from the group of alkali metal halides, alkaline earth metal halides, earth metal halides and mixtures thereof as mineralizer at 900.degree. to 1,300.degree. C. The coated spinel color pigments are suitable for the production of ceramic decorations with improved contour sharpness.