| 摘要 |
PURPOSE:To produce metallic magnetic powder having excellent particle orientation property with less sintering by coating the surfaces of particles consisting of needle-like iron oxyhydroxide and/or iorn oxide with fine particles SiO2 then with Al(OH)3 then subjecting the particles to a heating and reducing treatment in a reducing gaseous atmosphere. CONSTITUTION:Needle-like iron oxyhydroxide and/or needle-like iron oxide are thoroughly dispersed in water contg. anionic surfactants such as sodium hexametaphosphate and sodium polycarboxylate. The surfaces of the dispersed raw material particles are coated with 0.5-5.0wt% fine particles SiO2 based on the iron atoms by neutralizing treatment of sodium silicate then with Al(OH)3 to form 0.1-3.0wt% Al2O3 based on the iron atoms. The Al(OH)3 in this case is formed by a neutralizing treatment with AlCl3, etc. After the coated particles are filtered, rinsed and dried, the particles are subjected to a reducing teratment at 300-600 deg.C in a reducing gaseous atmosphere such as H2. |
