Abstract: A process for preparing carbonyl iron silicide comprises heat treatment of an iron/silicon mixture comprising a) from 20 to 99.9% by weight of finely divided carbonyl iron and b) from 0.1 to 80% by weight of finely divided silicon powder. Also provided are a carbonyl iron silicide obtainable by alloying carbonyl iron with silicon and a carbonyl iron suicide which has a higher inductance than carbonyl iron powder.

Abstract: Phosphorus-containing iron powder is prepared by mixing carbonyl iron powder or whiskers with elemental phosphorus, heating the mixture and comminuting the product obtained to give a powder. The powder of the present invention has a particularly low content of extraneous elements.

Abstract: Finely divided phosphorus-containing iron is prepared by reacting iron pentacarbonyl with a volatile phosphorus compound, in particular PH.sub.3, in the gas phase. The resulting phosphorus-containing iron powders and iron whiskers have a particularly low content of extraneous elements.

Abstract: The invention relates to a method for preparing silicon-containing iron powders by thermal decomposition of a gas mixture comprising iron pentacarbonyl and, as a volatile silicon compound, a silane or a halogen-free organosilane in which the gas mixture flows through a heated reaction chamber and heating of the gas mixture is effected by thermal conduction. The silicon-containing iron powders obtained are distinguished by a particularly low impurity element content. The silicon-containing iron powders can be used for the fabrication of cores, magnets and radar-absorbing materials.

Abstract: .gamma.-Fe.sub.2 O.sub.3 pigments and Fe.sub.3 O.sub.4 pigments with a particle diameter of 2 to 100 nm, a saturation magnetization above 40 nTm.sup.3 /g, a remanence below 10 nTm.sup.3 /g, a Cr content below 40 mg/kg of pigment, a Cu content below 40 mg/kg of pigment and C content below 100 mg/kg of pigment and aqueous suspension of these pigments. The pigments are used in aqueous suspension in the medical sector, in particular as contrast agents in magnetic resonance imaging.

Abstract: Silicon oxide-coated solid particles are produced by decomposing silanes which contain at least one alkanoyloxy radical with water vapor and/or oxygen in the presence of the agitated solid particles.

Abstract: There are described luster pigments based on metal oxide-coated aluminum platelets wherein the substrate aluminum platelets have a total carbon content <0.1% by weight, and the preparation and use of these pigments.

Abstract: Iron whiskers are produced by thermal decomposition of iron pentacarbonyl vapor in an indirectly heated empty-space decomposer in which the cross-sectional area for entry of the iron pentacarbonyl into the empty-space decomposer is from 10 to 40% of the cross-sectional area of the empty-space decomposer, the mass flow density of the iron pentacarbonyl vapor, based on the cross-sectional area of the decomposer, is from 0.01 to 0.07 kg per square meter per second, and the temperature in the empty-space decomposer should at no point be below 360.degree. C.

Abstract: A process for dewaxing injection molded metal pieces consisting of a metal/binder mixture, wherein a metal oxide is added to the metal/binder mixture.

Abstract: Iron powder is prepared by thermal decomposition of iron pentacarbonyl in a cavity decomposer, with an average amount of from 4 to 8 kg per m.sup.2 per hour of iron carbonyl striking the heating surface, by a process in which the velocity of the inflowing stream is brought to about 0.2-4 kg per m.sup.2 per second of carbonyl vapor or vapor/inert gas mixture by changing the inlet cross-section.