| 摘要 |
PURPOSE:To obtain the magnetic recording medium devoid of fluctuations in reproduced output having excellent high output characteristics by a method wherein granular magnetic Fe2O4 particle is treated as a starting material and used as alpha-Fe2O3 particle, and then it is reduced by heat or by reoxidization if necessary. CONSTITUTION:The granular spinel type iron oxide particle powder, to be used for magnetically isotropic magnetic recording medium consisting of granular spinel type iron oxide particle having magnetic characteristics of magnetic coercive force of Hc250e and saturated magnetization of deltas70emu/g or above, and the granular magnetite particle which is synthesized from the aqueous solution containing Fe<2+> are used as starting materials. The above materials are formed into alpha-Fe2O3 particles by performing oxidization under heat of the temperature range of 600-850 deg.C in an oxidizing atmosphere. Then, they are reduced by heat of 250-450 deg.C in a reducing atmosphere, and besides, reoxidized in the temperature range of 150-400 deg.C in an oxidizing atmosphere if necessary. Through these procedures, the magnetic recording medium having no fluctuations in regenerated output and which is suitable for a floppy disk can be obtained. |
