| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide metal magnetic grain powder essentially consisting of iron, in spite of the fineness of the grains, which exhibits a high coercive force, has excellent oxidation stability and has a soluble salt content reduced as much as possible. <P>SOLUTION: The metal magnetic grain powder essentially consisting of iron contains cobalt of 20 to 50 atomic % expressed in terms of Co to the total Fe, aluminum of 3 to 15 atomic % expressed in terms of Al, and rare earth elements of 3 to 30 atomic % expressed in terms of rare earth elements. In the metal magnetic grain powder essentially consisting of iron, a mean major axis diameter is 0.02 to 0.065 μm, an axis ratio (major axis diameter/minor axis diameter) is ≥3, a crystallite size is 90 to 150 Å, and a coercive force is 159.2 to 222.9 kA/m (2,000 to 2,800 Oe). The content of soluble Na is ≤30 ppm, the content of soluble Ca is ≤100 ppm, and oxidation stability Δσs is ≤10%. <P>COPYRIGHT: (C)2003,JPO |
