| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a magnetic iron ultrafine particle having high saturation magnetization and high oxidation resistance and also to provide a composite material maintaining electrical insulation property and having excellent magnetic properties and a high electromagnetic wave absorbing effect. <P>SOLUTION: A magnetic iron ultrafine particle, which consists of an ultrafine particulate nucleus 1 composed mainly of iron, an iron oxide layer 2 formed on the surface of the ultrafine particulate nucleus 1 and a silicon oxide layer 3 coating the surface iron oxide layer 2, is subjected to heat treatment at 400 to 600°C in an atmosphere containing hydrogen gas to obtain a magnetic iron ultrafine particle consisting of the ultrafine particulate nucleus 1 and the silicon oxide layer 3 coating the ultrafine particulate nuclei. Such magnetic iron ultrafine particle is subjected to hydrophobilizing treatment using a silane coupling agent, a resin monomer is graft-polymerized to apply resin coating to the surface, and then shaping is done by heating under pressure to obtain a composite material. <P>COPYRIGHT: (C)2009,JPO&INPIT |
