Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Degussa Gmbh

Roland Schilling

Kai Schumacher

Harald Alff

Martin Moerters

Juergen Flesch

Christoph Batz-Sohn

Dieter Kerner

Stipan Katusic

Rainer Golchert

Matthias Schmitt

Helmut Roth

Volker Hamm

Thomas Schiener

Marcus Von Twistern

Ronald Ihmig

Martin MÖRTERS

Jürgen Flesch

Martin Mörters

Aluminum oxide powder in the form of aggregates of primary-particles, which has a BET surface area of from 10 to 90 m2/g and comprises as crystalline phases, in addition to gamma-aluminum oxide and/or theta-aluminum oxide, at least 30% of delta-aluminum oxide. It is prepared by vaporizing aluminum chloride and burning the vapor together with hydrogen and air, the ratio of primary air/secondary air being 0.01 to 2, the exit speed vof the reaction mixture from the burner being at least 10 m/s, the lambda value being 1 to 4, the gamma value being 1 to 3 and the value of gamma*v/lambda being greater than or equal to 55. Dispersion comprising the aluminum oxide powder. Coating composition comprising the dispersion.

Aluminium oxide powder, dispersion and coating composition

Aluminium oxide powder produced by flame hydrolysis and consisting of aggregates of primary particles, having a BET surface area of from 100 to 250 m/g, a dibutyl phthalate absorption of from 50 to 450 g/100 g of aluminium oxide powder, which powder shows only crystalline primary particles in high-resolution TEM pictures. It is prepared by vaporizing aluminium chloride, transferring the vapour by means of a carrier gas to a mixing chamber and, separately therefrom, supplying hydrogen, air (primary air), which may optionally be enriched with oxygen and/or may optionally be pre-heated, to the mixing chamber, then igniting the mixture of aluminium chloride vapour, hydrogen, air in a burner and burning the flame into a reaction chamber that is separated from the surrounding air, subsequently separating the solid material from the gaseous substances and then treating the solid material with steam and optionally with air, the discharge rate of the reaction mixture from the mixing chamber into the reaction chamber being at least 10 m/s, and the lambda value being from 1 to 10 and the gamma value being from 1 to 15. It can be used as an ink-absorbing substance in ink-jet media.

Aluminium oxide powder produced by flame hydrolysis and having a large surface area

Titanium-aluminium mixed oxide powder with a proportion of aluminium oxide of less than 1 wt. % or a proportion of titanium dioxide of less than 5 wt. %, wherein the sum of the proportions of titanium dioxide and aluminium oxide is at least 99.7 wt. %. It is produced by transferring a vaporous starting compound of the quantitatively greater component of the mixed oxide into a mixing chamber by means of primary air and a vaporous starting compound of the quantitatively smaller component of the mixed oxide by means of an inert gas, and burning the mixture mixed with hydrogen in a mixing chamber into a reaction chamber. It can be used as a catalyst support.

Titanium-aluminium mixed oxide powder

Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 200&#xb1;25 m/g, wherein the aggregates display an average surface area of 7000 to 12000 nm, an average equivalent circle diameter (ECD) of 80 to 100 nm and an average circumference of 850 to 1050 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 1570 to 1630&#xb0; C. is obtained. It can be used as a filler.

Pyrogenically produced silicon dioxide powder

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Roland Schilling