| 摘要 |
PURPOSE:To obtain metal magnetic particle powder high in coercive force Hc, in metal magnetic particle powder using iron carbonate series goethite particle as a starting raw material, by incorporating Co and specifying the X-ray particle size, the major axis and minor axis and the axial ratio. CONSTITUTION:This metal magnetic particle powder is the one with a spindle shape contg. Co or Co and Al, and in which the X-ray particle size is regulated to 120 to 160Angstrom , the average major axis to 0.05 to 0.18mum, the minor axis to 0.010 to 0.018mum, the axial ratio (the major axis/the minor axis) to 4 to 15 and the coercive force Hc to 1700 to 2200Oe. For obtaining the same powder, suspension S contg. FeCO3 obtd. by bring an alkaline aq. soln. of carbonic acid C into reaction with an aq. soln. of ferrous salt F or contg. precipitate is aged in a nonoxidizing atmosphere. After that, an oxygen-contg. gas in passed through the suspension S, and an oxidizing reaction is brought into to give goethite having a spindle shape. At this time, in the suspension S before the oxidizing reaction, Co compounds are allowed to exist by 1.0 to 8.0mol.% expressed in terms of Co to Fe<2+> in the aq. soln. F. The obtd. an iron contg. goethite particles are dehydrated under heating and is reduced under heating in a reducing gas. |
