| 摘要 |
PURPOSE:To economically obtain high-purity hexagonal cobalt magnetic powder useful as perpendicular magnetic recording media in high yield, by directly reducing Co(OH)2 with hydrogen in water which is a reaction medium in the liquid phase. CONSTITUTION:0.1-20wt% fine Co(OH)2 powder, e.g hexagonal plate form of hexagonal crystal lattice having 0.01-1mum particle size, etc., is added to water which is a reaction medium and, as necessary, 0.0001-0.1wt% surfactant is added, thoroughly blended, stirred at 150-300 deg.C under 5-150kg/cm<2> in the presence of H2 and reductively reacted while heating for several sec-20hr. The resultant formed Co fine particles are then filtered, washed and dried to afford the aimed magnetic powder of hexagonal cobalt fine particles which are fine particulate powder having 0.01-1mum particle size, 1:2-10 ratio of the particle size to the thickness, ferromagnetism of 100-150emu/g saturation magnetization and 200-2,000.Oe coercive force.
|
