| 摘要 |
PURPOSE:To form a film on the particles of magnetic metallic powder with easy control and to provide high ignition preventive powder thereto without decreasing satd. magnetization with a safe and simple stage by coating the surfaces of said particles with a fluoride. CONSTITUTION:The magnetic metallic powder consisting essentially of iron and contg. Co, Ni, Cr, etc. is treated with hydrogen fluoride and/or hydrogen fluoride-cong. compd., fluorine and/or fluorine compd. at a prescribed temp. (for example, by passing a gas for the above-mentioned fluorination for a prescribed period, etc.). The film of the fluoride of the above-mentioned metal is thus formed nearly stoichiometrically and extremely easily on the surface of the metallic powder particles. The magnetic metallic powder is preferably treated with hydrogen fluoride or fluorine-contg. gas and further an inert gas or reducing gas for diluting said gases in a 200-820 deg.C range. |
