Abstract: Fumed silicon dioxide powder with a BET surface area of 20 to 35 m2/g, characterized in that a) the number-based median particle diameter is 60 to 150 nm, and b) the proportion of particles with a diameter of 200 nm or more is at most 10%, and c) the proportion of particles with a diameter of up to 60 nm is at most 20%, based in each case on the total number of particles.

Abstract: 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.

Abstract: Fumed silicon dioxide powder with a BET surface area of 20 to 35 m2/g, characterized in that a) the number-based median particle diameter is 60 to 150 nm, and b) the proportion of particles with a diameter of 200 nm or more is at most 10%, and c) the proportion of particles with a diameter of up to 60 nm is at most 20%, based in each case on the total number of particles.

Abstract: Mixed oxide powder consisting of particles with the components zirconium dioxide, aluminium oxide and at least a third component selected from the group including yttrium oxide, magnesium oxide or calcium oxide, wherein mixed oxide powder has an aluminium oxide content 0.01 to 10 wt. % and is homogeneously distributed in the mixed oxide particles, the content of aluminium oxide, zirconium dioxide and yttrium oxide is at least 99.5 wt. %, based on the total quantity of the powder, and the BET surface area is 20 to 80 m2/g. It is obtained by atomising a solution containing at least one starting compound for each of aluminium oxide, zirconium dioxide and the third component, allowing the atomised solution to react with oxygen in a reaction chamber at a reaction temperature 700 to 15000° C., cooling the hot gases and the solid products and then separating the solid product from the gases. It can be used as a dental material.

Abstract: Process for preparing mixed metal oxide powders Abstract Process for preparing a mixed metal oxide powder, in which oxidizable starting materials are evaporated in an evaporation zone of a reactor and oxidized in the vaporous state in an oxidation zone of this reactor, the reaction mixture is cooled after the reaction and the pulverulent solids are removed from gaseous substances, wherein at least one pulverulent metal, together with one or more combustion gases, is fed to the evaporation zone, the metal is evaporated completely in the evaporation zone under nonoxidizing conditions, an oxygen-containing gas and at least one metal compound are fed, separately or together, in the oxidation zone to the mixture flowing out of the evaporation zone, the oxygen content of the oxygen-containing gas being at least sufficient to oxidize the metal, the metal compound and the combustion gas completely.

Abstract: Nano-scale yttrium-zirconium mixed oxide powder in the form of aggregated primary particles having the following physico-chemical parameters:—BET surface area: from 40 to 100 m2/g,—da=from 3 to 30 nm, d,=mean, number-related primary particle diameter,—yttrium content, calculated as yttrium oxide Y2O3, determined by chemical analysis, from 5 to 15 wt. %, based on the mixed oxide powder,—yttrium contents of individual primary particles, calculated as yttrium oxide Y2O3 determined by TEM EDX, corresponding to the content in the powder+?10%,—content at room temperature, determined by X-ray diffraction and based on the mixed oxide powder—monoclinic zirconium oxide from <1 to 10 wt. %—tetragonal zirconium oxide from 10 to 95 wt. %—the content of monoclinic zirconium oxide after 2 hours' heating at 1300° C. being less than 1 wt. %,—carbon content less than 0.2 wt. %.

Abstract: 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.

Abstract: Indium-tin mixed oxide powder which consists of primary particle aggregates and contains 50 to 90% by weight indium oxide, calculated as In2O3, and 10 to 50% by weight tin oxide, calculated as SnO2. It is produced by atomising a solution of an inorganic indium compound and an organic tin compound and burning it in a flame. It may be used for the production of electrically conductive paints and coatings, solar cells and IR and UV absorbers and in medical technology.

Abstract: Mixed oxide powder consisting of particles with the components zirconium dioxide, aluminium oxide and at least a third component selected from the group including yttrium oxide, magnesium oxide or calcium oxide, wherein mixed oxide powder has an aluminium oxide content 0.01 to 10 wt. % and is homogeneously distributed in the mixed oxide particles, the content of aluminium oxide, zirconium dioxide and yttrium oxide is at least 99.5 wt. %, based on the total quantity of the powder, and the BET surface area is 20 to 80 m2/g. It is obtained by atomising a solution containing at least one starting compound for each of aluminium oxide, zirconium dioxide and the third component, allowing the atomised solution to react with oxygen in a reaction chamber at a reaction temperature 700 to 15000° C., cooling the hot gases and the solid products and then separating the solid product from the gases. It can be used as a dental material.

Abstract: Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m2/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.

Abstract: Zinc oxide powder is prepared by a process having the following steps a) generating of a zinc vapor-containing stream in a vaporization zone; b) oxidizing the zinc vapor by reaction with an oxygen-containing gas thereby forming zinc oxide powder in an oxidation zone; and c) cooling of the reaction mixture with water or an inert gas, and separation of the zinc oxide powder in a cooling/isolation zone, wherein aa) in the vaporization zone, a gas stream of an inert gas and a fuel gas is passed through a zinc melt which has a temperature of 450 to <900° C., thereby forming zinc vapor, the content of fuel gas being 1 to 50 vol. %, based on the sum of inert gas and fuel gas, and the molar quotient of zinc vapor to fuel gas being 0.01 to 50, and bb) in the oxidation zone, a second gas stream, which contains an oxygen-containing gas and steam, is added to the gas stream of zinc vapor, fuel gas and inert gas in an amount such that the temperature in the oxidation zone is from 500 to 1100° C.

Abstract: Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m2/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.

Abstract: The invention relates to a process for producing plastics mouldings with an electrically conductive coating by conventionally coating a moulding on one side with a varnish system composed of a) a binder, b) if desired, a solvent, c) if desired, further additives customary in varnish systems and d) from 10 to 300 parts by weight (based on component a)) of an electrically conductive metal oxide powder having an average primary particle size of from 5 to 130 nm and before curing the varnish film treating or storing the moulding in such a way that in that half of the varnish film which faces the boundary layer with the air the metal oxide powder particles accumulate in such a way that at least 65% of the particles are located in this half of the varnish film, and then curing the varnish film or allowing it to cure. The invention further relates to the mouldings which are producible in accordance with the invention.

Abstract: Indium-tin oxides with the following physical and chemical properties: 1 Mean primary particle size 1 to 200 obtained from TEM BET surface (DIN 66131) 0.1 to 300 m2/g Structure XRD cubic indium oxide tetragonal tin oxide Mesopores according to the 0.03 mL/g to 0.30 mL/g BJH method (DIN 66134) Macropores (DIN 66133) 1.5 to 5.