| 摘要 |
PURPOSE:To obtain a medium suitable for high density recording when the coating type medium for magnetic disk is to be formed using magnetic iron oxide powder by a method wherein magnetic iron oxide powder being made Co ions to diffuse uniformly inside of berthollide iron oxide particle having the degree of oxidation positioning at the middle between gamma-Fe2O3 and Fe3O4 is used as the iron powder. CONSTITUTION:Co ions are made to be diffused uniformly in the berthollide iron oxide particle having the degree of oxidation positioning at the middle beween gamma- Fe2O3 and Fe3O4, and using thus obtained magnetic iron oxide powder, the coating type medium for magnetic disk is formed. To put it concretely, Co doped type berthollide iron oxide powder being made adding quantity of Co therein as 0.9- 1.25% to the whole quantity of Fe and having the value of degree of oxidation Fe<2+>/Fe<3+> of 0.17-0.21 is used ot obtain iron oxide powder having magnetic resistance of 600-700 oersted. To manufacture this disk, iron oxide powder thereof is made to be dispersed in a thermosetting resin and a solvent, it is applied on a substrate, it is put in an inert gas atomosphere containing residual O2 of concentration less than 200ppm in undried condition, and baking and hardening treatment is performed at 150-230 deg.C for 1-3hr. |
