Degussa Aktiengesellschaft

Berthold Trageser

Markus Pridoehl

Guido Zimmermann

Heiko Gottfried

Stefan Heberer

Paul Roth

Heike Muehlenweg

Christian Janzen

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 m /g. The dispersion can be produced by dispersing the abrasive particles with an energy of at least 200 kJ/m 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).

Dispersion containing pyrogenically manufactured abrasive particles with superparamagnetic domains

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.

Superparamagnetic oxidic particles, processes for their production and their use

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Freigericht, Germany

Berthold Trageser