| 摘要 |
PROBLEM TO BE SOLVED: To obtain fusiform goethite microparticle powder favorable in particle size distribution, having excellent powder coercive force distribution(SFDr), large saturation magnetization value and high oxidation stability, favorable in squareness ratio (Br/Bm), and capable of giving fusiform metallic magnetic particle powder consisting mainly of iron. SOLUTION: This powder consisting of fusiform goethite particles contains 10-45 atom% of Co and 5-20 atom% of Al, each based on the total Fe, has an average major axis of 0.05-0.18 μm and a size distribution (standard deviation/average major axis) of <=0.24; wherein each of the particles is composed of seed crystal portion and surface layer portion in the weight ratio of (30:70) to (80:20), the Co is present both in the seed crystal and surface layer portions, while the Al in the surface layer alone. |
