METAL MAGNETIC POWDER, MANUFACTURE THEREOF AND COATING FILM FOR MAGNETIC RECORDING MEDIUM

PROBLEM TO BE SOLVED: To satisfy static magnetic characteristics and to improve dispersing property, filling property and oxidation resistance by using metal magnetic powder in a spindle shape, wherein Fe is contained by specified weight% or more, rare earth element and Co are contained by a specified weight rate with respect to Fe And S and Cl are both made to be the specified contents or less. SOLUTION: In the slurry of a spindle-shaped goethite containing Fe by 50wt.% or more at an axial ratio of 8.2, an aqueous solution 6 of hydrate of cobalt nitrate is added so that Co/Fe becomes 10-40wt.%. A compound, whose main component is cobalt hydroxide, is formed on the surface of particles. An aqueous solution 1 of hydrate of calcium acetate is added, and air is blown in. The aqueous solution of lanthanum is added so that La/Fe becomes 1-15wt.%. Furthermore, the aqueous solution of aluminum nitrate is dripped, and a compound, whose main component is the hydroxide of La and Al is formed. Washing is performed by ion exchange water until both S and Cl become 200ppm or less. The particles of a precursor are aligned. After high- temperature treatment, reduction and surface oxidation are performed. Thus, the metal magnetic powder having the excellent static magnetic characteristics and oxidation resistance and the high filling property is obtained.