PURPOSE: To obtain the titled metallic magnetic particles of high coercive force and of large saturating magnetization by hydrothermally treating the acidic suspension of β-FeOOH particles under a specified condition, and reducing it by heating.
CONSTITUTION: The acidic suspension containing β-FeOOH particles of ≥150m2/g specific surface area with <0.1mol cocn. is hydrothermally treated in 100W130°C temp. to produce hematite particles of uniform sized isotropic shape. These hematite particles are reduced by heating in a reductive gas to produce metallic magnetic particles main component of which is uniform sized and isotropic shaped iron. These metallic magnetic particles are submerged into the liquid of toluene which is evaporated to make stable oxydized films on the surface of the particles lest the particles should be suddenly oxydized when they are taken out in the air. Thus, the metallic magnetic particle powder of about ≥2500e coercive force and of ≥170emμ/g saturating magnetization is obtained.
KUROKAWA HARUMI
MISAWA HIROMITSU
