PURPOSE: To provide the titled needle crystal iron alloy magnetic particulate powder uniform in a particle size, having no dendritic particle mixed therein, large in a specific surface area and having high coercive force and large saturation magnetization, comprising a needle crystal iron alloy magnetic particle containing Si, Cr and Ni.
CONSTITUTION: O2-containing gas is passed through a suspension with a pH of 11 or more containing Fe(OH)2 obtained by reacting a ferrous salt (e.g. ferrous sulfate) and an alkali aqueous solution containing NaOH or the like to form a needle crystal α-FeOOH particle by oxidation. IN this case, either one of the alkali aqueous solution and the aforementioned suspension pripor to performing the aforementioned oxidation reaction, water soluble silicate (e.g., sodium silicate) is added in an amount of 0.1W1.7atom% as Si to Fe. In addition, water soluble Cr salt (e.g., chromium sulfate) is further added to the liquid prior to or during the aforementioned oxidation reaction in an amount of 0.1W5.0atom% as Cr to Fe and water soluble Ni salt (e.g., nickel sulfate) in an amount of 0.1W7.0 atom% as Ni. By this method, an objective needle crystal α-FeOOH particle containing Si, Cr and Ni is obtained.
OKUDA YOSHIROU
HARADA TOSHIHARU
MUKOUZAKA AKIRA
IMAI TOMOYUKI
| JPS55148705A | 1980-11-19 | |||
| JPS5532652A | 1980-03-07 | |||
| JPS5620105A | 1981-02-25 | |||
| JP39020939A |
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