Degussa Aktiengesellschaft

Degussa Gmbh

Evonik Degussa Gmbh

Ralph Brandes

Stipan Katusic

Hauke Jacobsen

Andreas Schulz

Jorg Sperlich

Helmut Mangold

Kai Schumacher

Günther Michael

Werner Hartmann

Stefan Heberer

Naruyasu Ishibashi

Rainer Hahn

Takeyoshi Shibasaki

Thomas Scharfe

Matthias Rochnia

Norbert Giesecke

Michael Kröll

Alfons Moster

Ronald Apel

Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90&#xb1;15 m/g, wherein the aggregates display an average surface area of 10000 to 20000 nm, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising HSiCl, HSiCl, HSiCl, CHSiCl, (CH)SiCl, (CH)SiCl and/or (n-CH)SiClare mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890&#xb0; C. is obtained. Dispersion containing the pyrogenically produced silicon dioxide powder.

Pyrogenically produced silicon dioxide powder and dispersion thereof

A dispersion of pyrogenically produced cerium oxide, which does not contain any particles larger than 1 &#x3bc;m, is produced by dispersing a pyrogenically produced cerium oxide in water by means of a dissolver, centrifuging it, separating the supernatant from the bottom product, and again dispersing the supernatant by means of ultrasound. The dispersion can be used for chemical-mechanical polishing (CMP).

Dispersion of pyrogenically produced cerium oxide

Pyrogenically produced aluminum-silicon mixed oxides with a BET surface of more than 300 m/g and a composition of 0.01 to 99.99% by wt. AIO, remainder SiOare produced in accordance with the method of flame pyrolysis or preferably flame hydrolysis by a joint combustion of the gaseous raw substances. They can be used to produce coating colors, especially for inkjet papers or inkjet foils or other inkjet materials.

Pyrogenically produced aluminum-silicon mixed oxides

The invention relates to spherical colored pigments having an average particle diameter of less than 10 .mu.m on the basis of an oxide, a mixed oxide or a silicate. The pigments are obtainable by means of spray-pyrolysis technology: a solution containing oxide-forming or silicate-forming metal compounds is converted into an aerosol and the latter is fed, preferably after predrying, to a pyrolysis reactor; the pigment is separated from the pyrolysis gas. The colored pigments according to the invention are suitable for the production of ceramic decorations and for the coloring of plastics, synthetic foils, fibers and also lacquers. By reason of the spherical shape, unusual technical application properties are achieved.

Spherical color pigments, process for their production and use thereof

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

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Princeton, NJ, United States of America

Ralph Brandes