IRON NITRIDE-BASED MAGNETIC POWDER

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PROBLEM TO BE SOLVED : To provide magnetic powder that maintains a needle-line shape, shows high coercive field strength as a fine particle state, and is suitable for a magnetic record medium for high-density recording such as a digital video tape and a backup tape for computers. SOLUTION : An oxide of iron or a hydroxide is used as a starting raw material for directly depositing at least one element selected from a rare earth element, boron, silicon, aluminum, and phosphorus to perform heating reduction treatment. After that, nitriding treatment is applied at a temperature not higher than reduction treatment temperature, thus obtaining iron nitride-based magnetic powder. In the iron nitride-based magnetic powder, iron and nitrogen are used as constitutional elements; at least Fe16N2 phase is included; the content of nitrogen to iron is 1.0-20.0 atom.%; and the shape of the iron nitride-based magnetic powder is a spindle or needle shape where the average size of a particle long axis is within 20-100 nm.