JPS6483605A - Production of superfine metal powder - Google Patents

Abstract

PURPOSE:To produce superfine powder of a metal having excellent magnetic characteristics by diluting the carbonyl compd. of a transition metal with an inert gas such as Ar, adding a sulfurous org. compd. thereto to form a gaseous mixture and subjecting the same to thermal cracking in a gaseous phase in a reaction tube impressed with a specific magnetic field. CONSTITUTION:The carbonyl compd. of the transition metal such as Fe(CO)5 or Ni(CO)4 is introduced from an introducing pipe 1 into a mixing chamber 2 to which the inert gas such as N2 or Ar is supplied from another introducing pipe 3 and further, the sulfurous org. compd. such as mercaptans is added thereto at <=0.1molar ratio of the carbonyl compd. to form the dilute gaseous mixture contg. <=3vol.% carbonyl compd.. The gaseous mixture is introduced into the reaction tube 4 applied with >=100 gauss magnetic field by an electromagnet, permanent magnet, etc., 5, and is heated for <= seconds at >=400 deg.C, by which the gaseous mixture is thermally cracked. The superfine powder of the transition metal such as Fe or Ni having <=0.5mu average grain size and the excellent magnetic characteristics such as high coercive force and high saturation magnetization is thus produced.