| 摘要 |
PURPOSE:To obtain the titled particle having low contents of Fe3O4 and elemental carbon and having controllable coercive force, by passing oxygen gas through a specific suspension, filtering and drying the produced Ni-containing iron alpha- oxyhydroxide and carbonizing the product. CONSTITUTION:A suspension is produced by mixing an aqueous solution of a nickel salt, an aqueous solution of an iron (II) salt and an alkaline aqueous solution. Oxygen or an oxygen-containing gas is passed through the suspension and the produced Ni-containing iron alpha-oxyhydroxide is separated by filtration, dried and carbonized to obtain the objective particle. As an alternative method, the above particle can be produced by (1) preparing a slurry composed of iron oxyhydroxide or iron oxide particles, a water-soluble nickel salt and water, (2) adding a reagent capable of converting the above nickel salt to a hardly soluble nickel compound to the slurry to cover the surface of the particle with a hardly soluble nickel compound and (3) filtering, drying and carbonizing the product. The carbonization agent is CO, methanol, methyl formate, etc. |
