| 摘要 |
PROBLEM TO BE SOLVED: To produce metal magnetic powder capable of obtaining a high density magnetic recording medium having satisfactory preservation stability and magnetic properties. SOLUTION: Through a stage where Al-containing iron oxyhydroxide is heated at 250 to 400°C to fix Al as Al<SB>2</SB>O<SB>3</SB>, then, a rare earth element (inclusive of Y) is incorporated therein, and the obtained powder of iron oxide comprising Al and a rare earth element (inclusive of Y) is heated and reduced in a reducing atmosphere, and a stage where water washing is performed before the incorporation of a rare earth element (inclusive Y) and after the fixing of Al as Al<SB>2</SB>O<SB>3</SB>, the acicular ferromagnetic metal powder in which the content of the group 1a elements in the Periodic Table is≤0.05 wt.%, and, if required, aluminum of 0.1 to 30 atomic% to the total content of the metal elements, and further, a rare earth element (inclusive of Y) of 0.1 to 10 atomic% to the total content of the metal elements are incorporated, and also, the residual amount of the group 2a elements in the Periodic Table to be made soluble is≤0.1 wt.% is obtained. COPYRIGHT: (C)2006,JPO&NCIPI
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