Yoshiteru Kageyama

Synthesis and Magnetic Properties of Ultrafine Iron Particles Prepared by Pyrolysis of Carbonyl Iron

Magnetic characteristics of fine iron particles prepared by a new chemical process, were studied. In this semi-industrial process, iron pentacarbonyl, Fe(CO)5 was used as a starting material, and it was thermally decomposed under a magnetic field. Diameter of obtained particles was between 150 and 250 A, and the particles were aligned along the magnetic field like a necklace. The highest coercive force appeared when particle diameter was about 200 A. To stabilize the particles, surfaces of particles were slightly oxidized before they were exposed to the open air. The saturation magnetization of treated particles was about 70% of the bulk value. Some test tapes were made by using these fine iron particles.