摘要:
Process for preparing a metal oxide powder, in which starting materials are evaporated and oxidized, wherein a metal melt in the form of droplets and one or more combustion gases are fed to the evaporation zone of a reactor, where the metal melt is 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 metal and the combustion gases completely.
摘要:
Pyrogenic, oxidic particles contain superparamagnetic metal oxide domains with a diameter of 3 to 20 nm in a non-magnetic metal or non-metal oxide matrix. The particles display a chloride content of 50 to 1000 ppm. The particles are produced by pyrogenic processes by mixing the precursor of the superparamagnetic domains and the precursor of the non-magnetic metal or non-metal oxide matrix in a flame with air and/or oxygen and fuel gas and reacting this mixture in a flame. The particles can be used as ferro fluids, for example.
摘要:
An aqueous dispersion containing abrasive particles comprises abrasive particles having superparamagnetic metal oxide domains in a non-magnetic metal oxide or non-metal oxide matrix. The abrasive particles of the aqueous dispersion can have an average particle size of below 400 nm and a BET surface area of 50 to 600 m2/g. The dispersion can be produced by dispersing the abrasive particles with an energy of at least 200 kJ/m3 using a device in which the abrasive particles are first subjected to high pressure, then decompressed through a nozzle so that the abrasive particles collide with one another or against sections of wall in the device. The aqueous dispersion can be used for chemical mechanical polishing (CMP).