Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Michael Kraemer

Stipan Katusic

Peter Kress

Michael Kroell

Edwin Staab

Markus Pridoehl

Hartmut Wiggers

Frank-Martin Petrat

Paul Roth

Guido Zimmermann

Stefan Heberer

Horst Miess

Guenther Michael

Peter Albers

Process for preparing a mixed metal oxide powder, in which oxidizable starting materials are evaporated and oxidized, the reaction mixture is cooled after the reaction and the pulverulent solids are removed from gaseous substances, wherein as starting materials, at least one pulverulent metal and at least one metal compound, the metal and the metal component of the metal compound being different and the proportion of metal being at least 80% by weight based on the sum of metal and metal component from metal compound, together with one or more combustion gases, are fed to an evaporation zone of a reactor, where metal and metal compound are evaporated completely under nonoxidizing conditions, subsequently, the mixture flowing out of the evaporation zone is reacted in the oxidation zone of this reactor with a stream of a supplied oxygen-containing gas whose oxygen content is at least sufficient to oxidize the starting materials and combustion gases completely.

Process for preparing mixed metal oxide powders

An aggregated crystalline silicon powder with a BET surface area of 20 to 150 m/g is provided. The aggregated silicon powder may be doped with phosphorus, arsenic, antimony, bismuth, boron, aluminium, gallium, indium, thallium, europium, erbium, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, dysprosium, holmium, thulium, lutetium, lithium, ytterbium, germanium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, or zinc.

Nanoscale crystalline silicon powder

Process for the production of a metal oxide powder having a BET surface area of at least 20 m/g by reacting an aerosol with oxygen in a reaction space at a reaction temperature of more than 700&#xb0; C. and then separating the resulting powder from gaseous substances in the reaction space, wherein

Process for the production of metal oxide powders

An aggregated crystalline silicon powder with a BET surface area of 20 to 150 m/g is provided. The aggregated crystalline silicon may be doped with a doping component and can be used to produce electronic components.

Aggregated crystalline silicon powder with a BET surface area of 20 to 150 m/g. It is prepared by subjecting at least one vaporous or gaseous silane and optionally at least one vaporous or gaseous doping material, an inert gas and hydrogen to heat in a hot wall reactor, cooling the reaction mixture or allowing the reaction mixture to cool and separating the product from gaseous substances in the form of a powder, wherein the proportion of silane is between 0.1 and 90 wt. %, with respect to the sum of silane, doping material, hydrogen and inert gases, and wherein the proportion of hydrogen, with respect to the sum of hydrogen, silane, inert gas and doping material, is in the range 1 mol. % to 96 mol. %. It can be used to produce electronic components.

Cerium oxide powder having carbonate groups and made of crystalline primary particles containing cerium oxide and having carbonate groups on the surface and in a region close to the surface, and having a BET surface area of from 25 to 150 m/g, a mean diameter of from 5 to 50 nm, a carbonate concentration in the region close to the surface decreasing inwardly from the surface, a carbon content due to carbonate groups on the surface of from 5 to 50% by area, a carbon content due to carbonate groups at a depth of about 5 nm in a region close to the surface of from 0 to 30% by area, a content of cerium oxide calculated as CeOand based on the powder of at least 99.5% by weight and a content of organic and inorganic carbon of from 0.01 to 0.3% by weight. A dispersion containing this powder.

Cerium oxide powder and cerium oxide dispersion

Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m/g, which is in the form of aggregates, the aggregates being composed of particles having different morphologies, and 0-10% of the aggregates being in a circular form, 30-50% being in an ellipsoidal form, 30-50% being in a linear form and 20-30% being in a branched form. It is prepared by reacting a starting mixture containing zinc vapour, a combustible gas and steam or a mixture of steam and carbon dioxide in a flame with an oxygen-containing gas in an oxidation zone, cooling the hot reaction mixture in a quenching zone and separating the solid material from the gas stream, the amount of oxygen in the oxidation zone being greater than the amount necessary for the complete oxidation of the combustible gas and the zinc vapour. The zinc oxide powder can be used as a constituent of sun protection compositions for protection against UV radiation.

Zinc oxide powder aggregates present in circular, ellipsoidal, linear and branched form

Polycrystalline cerium oxide powder in the form of aggregates of primary particles with a specific surface of between 70 and 150 m/g, an average primary particle diameter of between 5 and 20 nm and an average, projected aggregate diameter of between 20 and 100 nm. It is produced in that an aerosol is reacted in a flame obtained from a hydrogen-containing combustible gas and primary air and the solid obtained is then separated from the gaseous substances.

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Schoeneck-Kilianstaedten, Germany

Michael Kraemer