PURPOSE: To stably manufacture metallic magnetic super fine particles having excellent magnetic characteristic suitable for high density magnetic recording medium, etc., by executing gas phase thermal decomposition to a transition metal carbonyl compound in the specific condition.
CONSTITUTION: In to a lower nozzle part 6 in a reaction tube 7, H2, CO of inert gas or mixed gas thereof are introduced at high temp. from an introducing pipe 1. On the other hand, low temp. mixed gas of the transition metal carbonyl compound 2 and dilution gas 3 is supplied and magnetic field is impressed in the reaction tube 7 with a magnet 8. The metal carbonyl compound is made to the metallic super fine particles restraining acicular shape with the gas phase decomposing reaction and fed to an oxidizing reaction tube 10 through a tubular passage 9 to form the oxide film on the surface with the oxidizing gas of O2 or steam, etc., from an introducing pipe 12. In this case, this is cooled with cooling water 14 at the exit of the reaction tube 7, and also by introducing the dilution gas toward tangential direction to the exit cross section of the reaction tube from an introducing pipe 15 to develop a circular flow, the stickness and the aggregation of the mutual metal fine particles and stickness to inner face of tube wall are prevented and the metallic magnetic powder having excellent magnetic characteristic is stably manufactured.
KAGEYAMA YOSHITERU
TERAMOTO TADASHI
