Abstract: A method for producing decorations which are color-stable in a porcelain firing (glost firing), and a pigment composition suitable for this method, is disclosed. Inclusion pigments based on heavy-metal sulfides and selenides in an oxidic or silicate casing, especially ZrSiO.sub.4, result in more color-stable decorations in a porcelain firing if color-stabilizing auxiliary agents from the series of Zn compounds, especially ZnO or zinc-containing glass frits, or cerium(III) or cerium(IV) compounds, especially CeO.sub.2, are used in the decorative layer and/or glaze layer as color-stabilizing auxiliary agents. The amount used in the decorative layer is generally 5 to 50% by weight in the case of ZnO and CeO.sub.2, relative to the inclusion pigment. The pigment composition contains at least one of the color-stabilizing auxiliary agents in addition to an inclusion pigment.

Abstract: Inclusion pigments are discolored having zirconium silicate as a casing component and chromium (III) oxide (Cr.sub.2 O.sub.3) as a discrete, included color compound. The included Cr.sub.2 O.sub.3 has a D.sub.50 value in the range of 0.1 to 3.0 .mu.m and a brilliant light green color. Contrary to non-included Cr.sub.2 O.sub.3 of identical value, the pigments of the present invention may be used for the preparation of decorations without problems and difficulties in their application and maintaining sharp lines and contours. The pigments are suitable for direct pressing and high temperature firing processes. They are prepared by fusing a mixture of zirconium dioxide, silicon dioxide, mineralizators and chromium oxide.

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.

Abstract: Disclosed are neutral blue zirconium-vanadium pigments which do not display the disadvantages of previously known generic pigments, namely the high green component and the low color intensity and insufficient reproducibility in the case of neutral blue pigments. The neutral blue pigments with a rather high color intensity and good reproducibility are doped in the host lattice with phosphorus in addition to vanadium and are characterized by their color values in the CIE L*a*b* system. In order to produce such pigments, a zirconium-free mixture of powdery ZrO.sub.2, an SiO.sub.2 source, a vanadium compound and a phosphorus compound with an atomic ratio of Zr:Si:V:P=1:(0.95-1.10):(0.05-0.20):(0.005-0.03) as well as of a fluoride mineralizer is annealed after intensive grinding at 700.degree. to 900.degree. C.

Abstract: Gray-black inclusion pigments are made using zirconium silicate as the encasing substance and carbon black particles as the inclusion phase by annealing a mixture of zirconium dioxide, a source for silicon dioxide, carbon black and mineralizers under reducing conditions at 900.degree.-1400.degree. C. The process uses zeolites with an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of more than 4, preferably more than 10, as the SiO.sub.2 source. The depth of the color can be increased by also using an adhesion agent, especially silicon oil. The use of the zeolites facilities the employment of different zirconium dioxide qualities and permits the production of pigments with higher carbon black inclusion rates.

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.

Abstract: Encapsulation pigments comprising chromophoric particles embedded in glaze-stable casings are prepared by means of calcination from the appropriate initial products. High yields and strong color intensities are obtained if the chromophoric substance or its initial compounds are bound in and/or to a zeolite and are calcined in this form with the remaining constituents.