| 摘要 |
PURPOSE:To obtain particles having excellent dispersiveness and magnetic characteristic by applying Ni compound onto alpha-oxy iron hydroxide particles composed uniformly of solid solution of Al, further applying silicon compound and alumina hydrate in the alkali water and then reducing them. CONSTITUTION:Oxygen-containing gas is caused to flow into water suspension containing ferrous salt, alkali compound and Al compound to execute oxidizing reaction in the liquid and the alpha-oxy iron hydroxide particles composed of solid solution of Al, is obtd. After filtrating this and washing with water, again this is suspended in the water, and after applying the Ni compound on the surfaces of the above particles in this suspension, further the silicon compound and alumina hydrate are applied on the particles in the alkaline suspension. The obtd. particles are filtrated and dried and burnt at >=400 deg.C under non- reducing gas atmosphere, and successively reduced. By this method, content of different kinds of metal existing on the particle surface can be regulated. |
