| 摘要 |
PURPOSE:To make satd. magnetic flux density and output substantially high and to permit good high-density recording by using platy iron nitride magnetic powder expressed by FexN (3.3>=x>=2) as magnetic powder. CONSTITUTION:The platy iron nitride magnetic powder expressed by FexN (3.3>=x>=2) has a planar or hexagonal planar shape, has the magnetic anisotropy in the direction perpendicular to the plate plane and has a much higher rate of satd. magnetization than the satd. magnetization of the conventional barium ferrite magnetic powder. A magnetic recording medium which has the high satd. magnetic flux density and output and high S/N ratio and is suitable for satd. magnetic flux density is obtd. if the magnetic layer is formed by using this kind of the iron nitride magnetic powder. Such platy iron nitride magnetic powder is produced by subjecting, for example, hexagonal planar alpha-Fe2O3 powder to a sintering preventive treatment by the formation of a silicic acid film on the particle surface or the like, then subjecting the same to reducing and nitriding by heating, etc. in a gaseous mixture composed of gas contg. nitrogen such as gaseous ammonia and gaseous hydrogen.
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