Basf Aktiengesellschaft

Franz L Ebenhoech

Reinhold Schlegel

Werner Ostertag

Gerd Wunsch

Erfried Voelkl

Theodor Mader

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.

Preparation of iron whiskers

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.

Preparation of iron powder

Finely divided metal oxides produced by combustion of metal carbonyls are separated from the stream of gas by filtration. Before filtration, the stream of gas is subjected to a permanent change of direction in a tubular zone. This change of direction must be sufficient to cause a centrifugal acceleration which is from at least 1,000 to 10,000 times the acceleration due to gravity.

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Ludwigshafen, Germany

Franz L Ebenhoech