MANUFACTURE OF NEEDLELIKE IRON-BASE FERROMAGNETIC METALLIC POWDER

摘要

PURPOSE:To obtain needlelike iron-base ferromagnetic metallic powder with high coercive force and high squareness by sticking a tungstic acid compound to needlelike iron oxyhydroxide or oxide powder and heat reducing the powder to prevent a decrease of the sintering and reducing speeds of the particles. CONSTITUTION:Needlelike iron oxyhydroxide or oxide powder is suspended in an aqueous soln. of a tungstic acid compound such as ammonium metatungstate and dispersed with stirring to stick the tungstic acid compound to the surfaces of the iron compound particles. The particles are then filtered and dried. The amount of the stuck compound is about 0.01-5% as (W/Fe+W)X100%. By this method needlelike iron-base ferromagnetic metallic powder useful as a powdered material for magnetic recording is obtd. economically.