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Ferromagnetic powder

  • US 6,506,264 B1
  • Filed: 08/10/2000
  • Issued: 01/14/2003
  • Est. Priority Date: 12/18/1998
  • Status: Expired due to Term
First Claim
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1. A ferromagnetic powder containing iron as the main component and containing more than 5 to 50 at. % Co, 0.1 to 30 at. % Al, 0.1 to 10 at. % of a rare earth element inclusive of Y, 0.05% by weight or less of an element belonging to Group 1a of the Periodic Table, and 0.1% by weight or less (inclusive of 0% by weight) of an element belonging to Group 2A of the Periodic Table,said powder comprising flat acicular particles having a mean major axis length of 0.01 to 0.40 μ

  • m and a crystallite diameter as determined by X-ray diffraction (Dx) of 50 to 250 angstroms, provided that the cross section diameter in the minor axis direction cut perpendicular to the major axis has a larger width and a smaller width, and that a cross section ratio in the minor axis direction, which is a larger width to smaller width ratio, is uniformly in the major axis direction greater than 1, and said powder yielding a σ

    s/Dx ratio of 0.7 or higher, wherein, σ

    s represents the saturation magnetization and Dx represents the crystallite size determined by X-ray diffraction.

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