| 摘要 |
PURPOSE:To avoid the oxidative reaction with time of ferro magnetic metal grains for maintaining the excellent magnetic properties thereof by a method wherein the magnetic powder is surface treated using an ion type organic compound having the filming over capacity. CONSTITUTION:When the title magnetic metal powder is manufactured by heat-treating e.g. hematite as a material for reduction in hydrogen gas stream, the surface is made porous to increase the ratio of surface area in comparison with the particle size. Furthermore, when the hematite is covered with an ion type organic compound, the produced molecular film seems to become a protective layer for restraining the oxidation apt to be induced near the surface layer of the metal grains. Besides, the bimolecular film fills the role of an interfacial activator; two long chain alkyl radicals and hydrophilic radical fill the role of a binder for the preparation of a magnetic paint; and the bond properties between a high molecular film as a carrier of this paint and the magnetic metal grains are enhanced so that the stiffness and the running friction coefficient of a magnetic tape thus manufactured by specified processes such as coating the carrier with the magnetic paint, etc., may be improved. |
