Method of producing magnetic material with alkaline borohydrides

A method of producing a magnetic material for a magnetic recording medium comprising:

• (a) preparing a solution of a reducing agent selected from the group consisting of borane, borazane, borohydride, sodium borohydride, potassium borohydride, dimethylaminoborane and diethylaminoborane and a hydroxide compound selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, barium hydroxide and calcium hydroxide;
• and
• (b) mixing the solution of step (a) with a solution of metal salts capable of forming a ferromagnetic material mainly comprising a ferromagnetic powder selected from the group consisting of Fe, Co, Fe-Co, Fe-Ni, Fe-Co-Ni and Co-Ni, said salt being a chloride, a sulfate, a nitrate, a formate, an acetate, a pyrophosphate, or a sulfamate;
• the concentration of reducing agent in the solution of step (a) being 0.002 to 10 mols per liter, the concentration of hydroxide ion in the solution of step (a) being 0.001 N to 0.6N, the concentration of the metal ions in said metal salt solution being 0.002 to 2 mols per liter and the ratio of borohydride to metal ion being 0.25:1 to 4:1;
• mixing step (b) being carried out at -10.degree. C to 65.degree. C and the particle size of the ferromagnetic powder product being 50 to 1000 A.