| 摘要 |
Acicular particles are produced with an average axial ratio of 3-20 and an average size of 0.1-2 microns, and contain an Fe carbide containing Fe5C2 as main component. An acicular Fe compound having a surface pH of at least 5 and selected from acicular Fe oxyhydroxide and acicular Fe oxide, is contact with a gas containing CO or a mixture of CO and H2, at a contact temperture of 250-400 deg.C at a gas flow rate of CO, or mixture of CO and H2 of 1-1000 ml(STP)/min. per grain of acicular Fe compound. Acicular aprticles have a high coercive force and outstanding magnetic field orientation and are useful in magnetic recording media.
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