Degussa Aktiengesellschaft

Cerdec Aktiengesellschaft Keramische Farben

Cerdec Aktiengesellschaft Kermische Farben

Norbert Giesecke

Bernd Dorbath

Andreas Schulz

Klaus-Dieter Fritsche

Stipan Katusic

Werner Hartmann

Hauke Jacobsen

Kai Dorer

Ralph Brandes

Rainer Schlodder

Werner Voelker

Karl A Starz

Jorg Sperlich

Wilan Jerke

Kerstin Ruhnau

The invention relates to pigments consisting of substantially spherical particles with a mean particle diameter of less than 10 .mu.m, on the basis of an oxidic or silicate substrate material with noble metal distributed extremely finely on and/or in the particles. Preferred pigments are purple-colored and are based on an oxide from the series SiO.sub.2, SnO.sub.2 and ZrO.sub.2 and gold as noble metal. The pigments are suitable for the production of ceramic decorations and for the dyeing of plastics, synthetic films and fibers as well as lacquers. Exceptional application properties are obtained by virtue of the spherical shape. The pigments are obtainable by a spray-pyrolysis process in which an aerosol consisting of a solution of at least one noble metal compound and an oxide- or silicate-forming precursor is subjected to pyrolysis; the pigment is separated from the pyrolysis gas.

Spherical pigments, process for producing them and use thereof

Decorative preparations according to the invention for producing gold-containing decorations, in particular decorations on fireable substrates, contain as a source of gold a ligand-stabilized gold cluster or a ligand-stabilized gold colloid and also an organic binder and/or an inorganic component from the group consisting of glass frits, silicates, oxides and oxide/silicate precursors. The preferred source of gold is Au.sub.55 [(C.sub.2 H.sub.5).sub.2 P(m-C.sub.6 H.sub.4 SO.sub.3 Na)].sub.12 Cl.sub.6 or a gold colloid stabilized with the same phosphane. Bright gold, burnished gold and lustre preparations contain, in addition to the source of ligand-stabilized gold, an organic binder. A decorative preparation for purple decorations generally also contains, in addition to the decorative color consisting of the source of gold and the inorganic components, a medium consisting of an organic binder and a solvent. The decorative preparations are suitable either for producing ceramic decorations or for coloring plastics and lacquers.

Decorative preparations for producing gold-containing decorations and

Prior art production of purple pigments based on colloidal gold on stovable/sinterable/fireable support material involves the reduction of a gold compound in the presence of a chemical reducing agent. Purple pigments may be produced more simply according to the invention by intimately mixing and/or grinding the support material and the gold compound in dry form or by bringing an aqueous solution or suspension of a gold compound and a support material into contact and then thermally treating the mixture at a temperature above the decomposition temperature of the gold compound and below the sintering temperature of the support material, wherein the gold compound is converted into colloidal gold.

Process for the production of purple pigments

Purple colors based on colloidal gold on stovable substrates and the use thereof for the production of purple decoration on glass, ceramics and porcelain are known. The production of such purple colors is elaborate. Agents according to the invention should be viewed as pigment precursors, wherein the pigment is formed during firing of the decoration. The agents contain a gold compound, with the exception of gold oxide, which may be decomposed to colloidal gold on firing of the decoration and a finely divided glass flux in a weight ratio of gold to glass flux of between 1:10 and 1:2,000. Preferred agents contain HAuCl.sub.4, Au.sub.2 S.sub.3, AuCN or KAu(CN).sub.2 as the gold compound and a lead-free glass frit as the glass flux. The agents may be obtained by grinding the glass flux with a gold compound. Purple decoration is obtained by applying the agent to the substrate to be decorated and storing at 400.degree. to 1,050.degree. C.

Process and agent for the production of purple decoration

New electromagnetic interference (EMI) shielding pigments based on silver coated carrier pigments are disclosed which have a wider activity spectrum and are more economically available than previously known shielding pigments. The carrier pigments used are platelet shaped, ferro- or ferrimagnetic, Fe-containing, naturally occurring or synthetically produced laminar minerals. The Ag coating amounts to 5 to 25% by weight, based on the carrier pigment. Shielding pigments, which may be prepared by conventional chemical deposition of Ag or by sputtering, may be used for the production of EMI protective coatings and EMI protective films.

EMI shielding pigments, a process for their preparation and their use

Bright, low carat gold-silver-alloy coatings which are ductile and have a thickness up to over 100 .mu.m are obtained from an electrolytic bath containing 0.5 to 25 g/l of gold in the form of alkali gold cyanide, 0.25 to 15 g/l of silver in the form of alkali silver cyanide and 10 to 200 g/l of alkali cyanide as well as 0.001 to 5 g/l of tellurium in the form of a water soluble tellurium compound.

Method and electrolytic bath for the deposition of low carat bright

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Bruchkobel, Germany

Norbert Giesecke