PROCESS FOR PRODUCING COBALT-CONTAINING MAGNETIC IRON OXIDE POWDER

摘要

Magnetic iron oxide particles (I) are produced by coating an iron (II) compound and a cobalt compound. The particles (I), used as starting material, are first coated with the iron (II) compound and then with the cobalt compound. The iron (II) compound is a hydroxide and/or hydrated oxide. The coating with the iron (II) compound and the cobalt compound is performed in a non-oxidising atmosphere, in order not to oxidise the iron (II) compound. The iron (II) compound and the cobalt compound are applied at a reaction temperature below the boiling point of the aqueous solution, especially at a temperature below 50 deg.C.