| 摘要 |
PURPOSE:To obtain magnetic iron powder for magnetic recording having excellent oxidation resistant stability by bringing the surface in the upper part of a liquid org. solvent suspension of an alkali (earth) metal salt into contact with an O2-contg. gas while stirring said suspension under heating. CONSTITUTION:Magnetic metal powder is suspended in the org. solvent dissolved with the alkali metal salt (e.g.; NaCl) and/or alkaline earth metal salt (e.g., BaCl2). For example, polyhydric alcohol such as EG, PG and glycerol and monohydric alcohol such as decyl alcohol are more particularly preferable as the above-mentioned org. solvent. While the resultant liquid suspension is kept stirred to the extent of mixing the same by a propeller stirrer, etc., under heating, the O2-contg. gas is blown into said liquid and is brought into contact with the surface in the upper part of the liquid suspension. The temp. of the liquid suspension in this case is more particularly preferably 100-300 deg.C. The concn. of O2 in the O2-contg. gas is preferably 0.1-25vol%. The dense film incorporated with the atoms of the metal for modification into the resultant oxide film is formed by the method of this invention and the magnetic iron powder having the excellent oxidation resistant stability is obtd.
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