Colored pigments based on oxide-nitrides, the preparation and use thereof

US5766336A · kind A · utility

Assignee

• Cerdec Aktiengesellschaft Keramische Farben · DE

Inventors

• Martin Jansen · Bonn, DE
• Hans-Peter Letschert · Bonn, DE

Key dates

• Filing date: Aug 21, 1995
• Grant date: Jun 16, 1998
• Expiry date: Aug 21, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08K3/013
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Colored pigments are provided from the green-yellow to red spectrum based on oxide-nitrides with two or three different cations Q, R and S in the crystal lattice, wherein the nitrogen to oxygen atomic ratio is determinative for the color. These pigments crystallise in the pyrochlore, spinel or elpasolite structure. Pigments in the perovskite are as provided with increased color brilliance. The color of the pigments can be adjusted in a wide range of the color spectrum during their preparation within a substance class with the cations Q, R and S and while retaining the crystal structure, by increasing or lowering the atomic ratio N to O in the oxide-nitride and bringing about the required charge balancing by replacing an equivalent quantity of the cation Q with the valency q by a cation R with the valency q+1. In order to prepare the pigments, a mixture of oxide-nitride-forming metal compounds in the atomic ratio of the cations according to the structural formula is calcined, preferably in the presence of mineralizers, under nitriding conditions at 700.degree.-1250.degree. C.