Process for producing ultrafine metal powder

Abstract

In a process for producing an ultrafine powder of a metal by subjecting a transition metal carbonyl compound to gas phase pyrolysis reaction, the improvement which comprises diluting said carbonyl compound with an inert gas or hydrogen to a concentration of 3 vol. % or less with optional addition of an oxygen-containing organic compound and/or a sulfur-containing organic compound in an amount of 0.0001 to 0.1 mol per mol of said carbonyl compound to prepare a gas mixture, and then carrying out gas phase pyrolysis reaction at 300.degree. C. or higher by allowing said gas mixture to reside for 5 seconds or less in a reaction system to which a magnetic field of 100 gauss or higher is being applied, thereby obtaining the ultrafine powder of said metal having a length of 1 micron or less, a coercive force of 800 oersted or higher and a saturation magnetization of 120 emu/g or higher.

Dependencies are inferred from the claim text.