| 摘要 |
PURPOSE:To obtain stably a suitable titled fine particle as magnetic powder for vertical magnetic recording by adding Sn<4+> or a bivalent element and Sn<4+> compound in the manufacture wherein other element is substituted for a part of iron atom consisting of titled ferrite. CONSTITUTION:An iron compound among Fe3O4, (FeO)x.Fe2O3 (0<x<1) and gamma-Fe2O3 and a compound contg. at least one kind of Ba, Sr and Pb are subjected to thermal treatment in water together with an oxidizing agent in an aq. alkali soln. to manufacture titled fine particle. In this case, different kinds of elements of M<2+>(bivalent element) and Sn<4+> are added in the thermal treatment in water or in the manufacture of said iron compounds. By this way, the fine hexagonal lamellar or titled lamellar whose coercive force is lowered suitably can be manufactured. Sodium stannate and SnCl4 as tetravalent Sn compound and bivalent compound such as Fe, Cu, Zn and Co as M<2+> compound are used. |
